Psoriasis — MCQs

Q: A 16-year-old boy presented with asymptomatic, multiple erythematous annular lesions with a collarette of scales at the periphery of the lesions present on the trunk. What is the most likely diagnosis?

Pityriasis rosea. ### Explanation The clinical presentation of multiple erythematous annular lesions with a characteristic **collarette of scales** at the periphery on the trunk is a classic description of **Pityriasis Rosea (PR)**. **Why Pityriasis Rosea is correct:** PR is an acute, self-limiting inflammatory dermatosis, often associated with Human Herpesvirus 6 or 7 (HHV-6/7). It typically begins with a single, large **"Herald Patch"** followed by a generalized eruption of smaller oval lesions. The scales in PR are unique; they are attached at the periphery and free in the center, forming a **"collarette"** appearance. On the back, these lesions follow the lines of cleavage, creating a **"Christmas Tree"** or "Fir Tree" distribution. **Why the other options are incorrect:** * **Pityriasis versicolor:** Presents as hypo- or hyperpigmented macules with fine, branny (furfuraceous) scaling. It is caused by *Malassezia* and does not typically show a peripheral collarette of scales. * **Pityriasis alba:** Commonly seen in children with atopy, presenting as ill-defined hypopigmented patches with fine scaling, usually on the face. It lacks the annular, erythematous nature of PR. * **Pityriasis rubra pilaris (PRP):** Characterized by follicular papules on an erythematous base, "islands of sparing," and orange-red palmoplantar keratoderma. It does not present with a collarette of scales. **High-Yield Clinical Pearls for NEET-PG:** * **Herald Patch:** The initial lesion (seen in 80% of cases), usually larger and more scaly than subsequent lesions. * **Hanging Curtain Sign:** When the skin is stretched across the long axis of the lesion, the scales tend to fold inwards (characteristic of PR). * **Treatment:** Usually conservative (reassurance); antihistamines for pruritus. * **Differential Diagnosis:** Secondary syphilis (always rule this out if lesions involve palms and soles; PR typically spares them).

Q: Civatte bodies are a characteristic histological feature of which condition?

Lichen planus. **Explanation:** **Civatte bodies** (also known as colloid or hyaline bodies) are a hallmark histopathological finding in **Lichen Planus**. They represent apoptotic or degenerated keratinocytes located in the lower epidermis or papillary dermis. **Why Lichen Planus is correct:** Lichen planus is characterized by a "lichenoid" or interface dermatitis where a dense, band-like lymphocytic infiltrate attacks the basal layer of the epidermis. This immune-mediated destruction leads to **liquefactive degeneration** of the basal cells. The shrunken, eosinophilic remnants of these dead keratinocytes are the Civatte bodies. They stain positively for PAS (Periodic Acid-Schiff) and contain IgM on direct immunofluorescence. **Why other options are incorrect:** * **Lichen simplex chronicus:** This is a result of repetitive scratching. Histology shows hyperkeratosis, hypergranulosis, and regular elongation of rete ridges (psoriasiform hyperplasia), but not basal cell apoptosis. * **Lichen sclerosus:** While it involves interface changes, its hallmark is significant subepidermal edema and homogenization of collagen (sclerosis) in the upper dermis, rather than prominent Civatte bodies. **NEET-PG High-Yield Pearls for Lichen Planus:** * **6 P’s:** Planar, Purple, Polygonal, Pruritic, Papules, and Plaques. * **Wickham Striae:** White reticular lines on the surface of lesions (due to focal hypergranulosis). * **Max-Joseph Spaces:** Small clefts between the epidermis and dermis due to extensive basal cell degeneration. * **Saw-tooth Rete Ridges:** Characteristic appearance of the epidermal-dermal junction. * **Koebner Phenomenon:** Development of lesions at sites of trauma (also seen in Psoriasis and Vitiligo).

Q: The "Hanging Curtain Sign" is characteristic of which dermatological condition?

Pityriasis Rosea. **Explanation:** The **Hanging Curtain Sign** is a classic clinical feature of **Pityriasis Rosea (PR)**. It is elicited by stretching the skin across the long axis of a herald patch or a secondary lesion. Due to the fine, "cigarette paper" like scaling and the way the scales are attached at the periphery (collarette scaling), the scales fold and hang down like a curtain when the skin is pinched or stretched. **Analysis of Options:** * **Pityriasis Rosea (Correct):** An acute, self-limiting inflammatory dermatosis. It typically begins with a **Herald Patch** (a single, large, erythematous scaly plaque) followed by a generalized eruption in a **"Christmas Tree" distribution** along the lines of cleavage (Langer’s lines). * **Psoriasis:** Characterized by the **Auspitz Sign** (pinpoint bleeding upon removal of scales) and **Grattage Test**. The scales are silvery-white and micaceous, not "curtain-like." * **Lichen Planus:** Known for the **6 P’s** (Planar, Purple, Polygonal, Pruritic, Papules, and Plaques) and **Wickham Striae**. It does not exhibit the hanging curtain sign. * **Hordeolum Externum:** This is an acute focal infection (usually Staphylococcal) of the eyelash follicle or associated glands (Zeis/Moll). It is an ophthalmological condition presenting as a painful eyelid bump, unrelated to scaly dermatoses. **High-Yield Clinical Pearls for NEET-PG:** * **Collarette of scales:** Scales in PR are attached at the periphery with free central edges. * **Herald Patch:** The initial lesion seen in 50-90% of cases. * **Etiology:** Associated with **HHV-6 and HHV-7** reactivation. * **Treatment:** Usually self-limiting (6-8 weeks); symptomatic relief with antihistamines or topical steroids.

Q: A 'herald patch' is characteristic of which of the following conditions?

Pityriasis rosea. ### Explanation **Correct Option: A. Pityriasis rosea** The **Herald Patch** (also known as the "mother patch") is the pathognomonic initial lesion of Pityriasis rosea. It is a single, large (2–6 cm), oval, erythematous, scaly plaque, typically appearing on the trunk. About 1–2 weeks later, a secondary eruption of smaller, similar-looking lesions follows, distributed along the lines of cleavage (Langer’s lines), creating the classic **"Christmas Tree" appearance**. The scales in Pityriasis rosea are characteristically attached at the periphery with a free central edge, known as **collarette scaling**. **Incorrect Options:** * **B. Pityriasis rubra pilaris (PRP):** Characterized by follicular papules on an erythematous base, "islands of sparing" (normal skin within affected areas), and orange-red palmoplantar keratoderma. * **C. Pityriasis lichenoides et varioliformis acuta (PLEVA):** Presents as a sudden eruption of polymorphous papules that undergo necrosis, crusting, and scarring (varioliform scars). * **D. Pityriasis alba:** A common, mild form of dermatitis seen in children (often associated with atopy), presenting as ill-defined hypopigmented patches with fine scaling, usually on the face. **High-Yield Clinical Pearls for NEET-PG:** * **Etiology:** Likely associated with **HHV-6 and HHV-7** reactivation. * **Distribution:** "Christmas tree" or "Fir tree" pattern on the back. * **Herald Patch Location:** Most commonly found on the trunk (90% of cases). * **Treatment:** Usually self-limiting (6–8 weeks). Pruritus is managed with antihistamines or topical steroids. * **Differential Diagnosis:** Secondary syphilis (always rule out if lesions involve palms and soles).

Q: What is the most common cause of psoriasis?

Autoimmune. **Explanation:** Psoriasis is fundamentally defined as a **chronic, T-cell mediated autoimmune inflammatory dermatosis**. The core pathophysiology involves the activation of the **IL-23/Th17 axis**, where dendritic cells and T-lymphocytes (specifically Th1 and Th17) release cytokines like TNF-α, IL-17, and IL-22. This "cytokine storm" triggers the rapid, uncontrolled proliferation of keratinocytes, leading to the characteristic thickened, scaly plaques. **Analysis of Options:** * **A. Autoimmune (Correct):** While the exact trigger is often unknown, the disease is driven by an aberrant immune response against self-antigens (like LL-37 or ADAMTSL5) in the skin. * **B. Hereditary:** Genetics play a significant role (e.g., **HLA-Cw6** is the strongest association), but it is considered a predisposing factor rather than the direct "cause." Not everyone with the gene develops the disease. * **C. Psychosomatic:** Stress is a well-known **trigger** or exacerbating factor for flares, but it does not cause the underlying pathology. * **D. Infective:** Certain infections (like Streptococcal pharyngitis) can trigger **Guttate psoriasis**, but the disease itself is not contagious or primarily infectious. **NEET-PG High-Yield Pearls:** * **Auspitz Sign:** Pinpoint bleeding after scraping a scale (due to thinning of suprapapillary epidermis). * **Koebner Phenomenon:** Development of lesions at sites of trauma (also seen in Vitiligo and Lichen Planus). * **Histology:** Look for **Munro’s microabscesses** (neutrophils in the stratum corneum) and **Kogoj’s pustules** (neutrophils in the stratum spinosum). * **Drug Triggers:** Beta-blockers, Lithium, Antimalarials, and NSAIDs (Mnemonic: **BLANS**).

Q: Which of the following drugs is NOT used in the management of psoriasis?

Chloroquine. In the management of psoriasis, the goal is to inhibit keratinocyte proliferation and modulate the immune response. **Why Chloroquine is the correct answer:** Chloroquine (and Hydroxychloroquine) is an antimalarial drug that is notoriously known to **exacerbate or trigger psoriasis**. It can induce a flare-up of stable plaque psoriasis or even precipitate a life-threatening **erythrodermic or pustular transformation**. The mechanism is thought to involve the inhibition of the enzyme transglutaminase and the stimulation of interleukin-8, leading to epidermal hyperproliferation. Therefore, it is strictly avoided in psoriatic patients. **Why the other options are incorrect:** * **Psoralens (Option A):** These are photosensitizing agents used in **PUVA (Psoralen + UVA)** therapy. They intercalate into DNA to inhibit rapid cell division. * **Methotrexate (Option C):** A folic acid antagonist that acts as a potent immunosuppressant and cytotoxin. It is a **gold standard systemic treatment** for severe plaque psoriasis, psoriatic arthritis, and erythrodermic psoriasis. * **Coal Tar (Option D):** One of the oldest topical treatments (e.g., Goeckerman regimen). It has anti-inflammatory and keratoplastic properties that help normalize keratinization. **NEET-PG High-Yield Pearls:** * **Drugs that aggravate psoriasis (mnemonic: B-L-A-C-K):** **B**eta-blockers, **L**ithium, **A**ntimalarials (Chloroquine), **C**orticosteroids (withdrawal), and **K** (Potassium) sparing diuretics/NSAIDs. * **First-line for localized psoriasis:** Topical Vitamin D3 analogues (Calcipotriol) and Corticosteroids. * **Drug of choice for Psoriatic Arthritis:** Methotrexate (though biologics like Secukinumab are increasingly used).

Q: Which among the following is the most common site affected by psoriasis?

Extensor surface. **Explanation:** Psoriasis is a chronic, immune-mediated inflammatory skin disorder characterized by well-demarcated erythematous plaques with silvery-white scales. **Why Extensor Surfaces are Correct:** The hallmark of chronic plaque psoriasis (the most common clinical variant) is its predilection for **extensor surfaces**. The most frequently involved sites are the **elbows, knees, and the scalp**. This distribution is attributed to the **Koebner phenomenon**, where skin lesions appear at sites of repetitive minor trauma or friction, which occurs more frequently on extensor surfaces. **Analysis of Incorrect Options:** * **Flexor surfaces:** Involvement of flexural areas (axilla, groin, submammary folds) is known as **Inverse Psoriasis**. It is less common and characterized by a lack of scaling due to moisture in the skin folds. * **Palms and soles:** While Palmoplantar Psoriasis is a recognized variant, it is significantly less common than the classic plaque type involving extensors. * **Oral mucosa:** Psoriasis rarely involves the oral mucosa. When it does, it may manifest as geographic tongue, but it is never the most common site. **High-Yield Clinical Pearls for NEET-PG:** * **Auspitz Sign:** Pinpoint bleeding upon removal of scales (due to thinning of the suprapapillary plate and dilated capillaries). * **Munro’s Microabscess:** Collection of neutrophils in the stratum corneum (pathognomonic histopathology). * **Grattage Test:** Scraping the lesion increases the visibility of silvery scales (candle grease sign). * **Woronoff’s Ring:** A pale halo of blanched skin surrounding a healing psoriatic plaque.

Q: Which of the following conditions produces pre-malignant lesions?

Lichen planus. **Explanation:** The correct answer is **Lichen planus (LP)**. This is because certain variants of Lichen planus, particularly **Oral Lichen Planus (OLP)** and **Vulvar Lichen Planus**, are recognized as **premalignant (potentially malignant) conditions**. Chronic inflammation and rapid cell turnover in these lesions can lead to the development of **Squamous Cell Carcinoma (SCC)**. The risk is highest in the erosive or atrophic subtypes of OLP, with a transformation rate of approximately 0.5% to 2%. **Why other options are incorrect:** * **Psoriasis:** Despite being a chronic inflammatory condition with rapid epidermal hyperplasia, psoriasis is **not** considered a premalignant condition. In fact, some studies suggest a lower incidence of skin cancer within psoriatic plaques themselves, though treatments like PUVA or methotrexate may independently increase malignancy risk. * **Erythema Multiforme:** This is an acute, self-limiting hypersensitivity reaction (often triggered by HSV or drugs). It does not involve chronic tissue remodeling or long-term cellular atypia, and thus carries no risk of malignant transformation. **High-Yield Clinical Pearls for NEET-PG:** * **Lichen Planus:** Characterized by the "6 Ps": Planar, Purple, Polygonal, Pruritic, Papules, and Plaques. Look for **Wickham striae** (white reticular patterns). * **Koebner Phenomenon:** Seen in both Psoriasis and Lichen Planus (development of lesions at sites of trauma). * **Other Premalignant Skin Conditions:** Actinic keratosis (most common), Bowen’s disease, Leukoplakia, and Xeroderma pigmentosum. * **Histopathology of LP:** "Saw-tooth" appearance of rete pegs and basal cell degeneration (liquefaction degeneration).

Q: Which of the following is NOT true regarding Munro's microabscess?

Debris consists of eosinophils. ### Explanation **Munro’s microabscess** is a hallmark histopathological feature of **Psoriasis**. **1. Why Option B is the correct answer (The False Statement):** Munro’s microabscesses consist of collections of **neutrophils**, not eosinophils. In psoriasis, there is a chemotactic drive (mediated by IL-8 and LTB4) that causes neutrophils to migrate from the papillary capillaries through the epidermis (Kogoj’s spongiform pustules) to the **stratum corneum**, where they form these microabscesses. Eosinophils are typically absent in classic psoriasis; their presence should prompt a search for other diagnoses like drug-induced psoriasiform eruptions. **2. Analysis of Incorrect Options (True Statements):** * **Option A (Seen in the stratum corneum):** This is the characteristic location. As neutrophils migrate upward, they get trapped within the parakeratotic scales of the cornified layer. * **Option C (Associated pustule may be present):** When these neutrophil collections become large and clinically visible, they are termed **Kogoj’s spongiform pustules** (seen in the stratum spinosum) or macro-pustules, as seen in Pustular Psoriasis. * **Option D (Seen in psoriasis):** It is one of the "cardinal" histopathological signs of Psoriasis Vulgaris. **3. High-Yield Clinical Pearls for NEET-PG:** * **Kogoj’s Spongiform Pustule:** Neutrophils in the **stratum spinosum** (multilocular). * **Munro’s Microabscess:** Neutrophils in the **stratum corneum**. * **Other Histopathology features of Psoriasis:** * **Acanthosis:** Thickening of the stratum spinosum with regular elongation of rete ridges ("Camel foot" appearance). * **Parakeratosis:** Retention of nuclei in the stratum corneum. * **Agranulosis:** Thinning or absence of the stratum granulosum. * **Auspitz Sign:** Pinpoint bleeding on scraping the scale due to thinning of the suprapapillary plate and dilated capillaries.

Psoriasis Indian Medical PG Practice Questions and MCQs

Question 1: A 16-year-old boy presented with asymptomatic, multiple erythematous annular lesions with a collarette of scales at the periphery of the lesions present on the trunk. What is the most likely diagnosis?

A. Pityriasis versicolor
B. Pityriasis alba
C. Pityriasis rosea (Correct Answer)
D. Pityriasis rubra pilaris

Explanation: ### Explanation The clinical presentation of multiple erythematous annular lesions with a characteristic **collarette of scales** at the periphery on the trunk is a classic description of **Pityriasis Rosea (PR)**. **Why Pityriasis Rosea is correct:** PR is an acute, self-limiting inflammatory dermatosis, often associated with Human Herpesvirus 6 or 7 (HHV-6/7). It typically begins with a single, large **"Herald Patch"** followed by a generalized eruption of smaller oval lesions. The scales in PR are unique; they are attached at the periphery and free in the center, forming a **"collarette"** appearance. On the back, these lesions follow the lines of cleavage, creating a **"Christmas Tree"** or "Fir Tree" distribution. **Why the other options are incorrect:** * **Pityriasis versicolor:** Presents as hypo- or hyperpigmented macules with fine, branny (furfuraceous) scaling. It is caused by *Malassezia* and does not typically show a peripheral collarette of scales. * **Pityriasis alba:** Commonly seen in children with atopy, presenting as ill-defined hypopigmented patches with fine scaling, usually on the face. It lacks the annular, erythematous nature of PR. * **Pityriasis rubra pilaris (PRP):** Characterized by follicular papules on an erythematous base, "islands of sparing," and orange-red palmoplantar keratoderma. It does not present with a collarette of scales. **High-Yield Clinical Pearls for NEET-PG:** * **Herald Patch:** The initial lesion (seen in 80% of cases), usually larger and more scaly than subsequent lesions. * **Hanging Curtain Sign:** When the skin is stretched across the long axis of the lesion, the scales tend to fold inwards (characteristic of PR). * **Treatment:** Usually conservative (reassurance); antihistamines for pruritus. * **Differential Diagnosis:** Secondary syphilis (always rule this out if lesions involve palms and soles; PR typically spares them).

Question 2: Civatte bodies are a characteristic histological feature of which condition?

A. Lichen simplex chronicus
B. Lichen planus (Correct Answer)
C. Lichen sclerosus
D. All of the above

Explanation: **Explanation:** **Civatte bodies** (also known as colloid or hyaline bodies) are a hallmark histopathological finding in **Lichen Planus**. They represent apoptotic or degenerated keratinocytes located in the lower epidermis or papillary dermis. **Why Lichen Planus is correct:** Lichen planus is characterized by a "lichenoid" or interface dermatitis where a dense, band-like lymphocytic infiltrate attacks the basal layer of the epidermis. This immune-mediated destruction leads to **liquefactive degeneration** of the basal cells. The shrunken, eosinophilic remnants of these dead keratinocytes are the Civatte bodies. They stain positively for PAS (Periodic Acid-Schiff) and contain IgM on direct immunofluorescence. **Why other options are incorrect:** * **Lichen simplex chronicus:** This is a result of repetitive scratching. Histology shows hyperkeratosis, hypergranulosis, and regular elongation of rete ridges (psoriasiform hyperplasia), but not basal cell apoptosis. * **Lichen sclerosus:** While it involves interface changes, its hallmark is significant subepidermal edema and homogenization of collagen (sclerosis) in the upper dermis, rather than prominent Civatte bodies. **NEET-PG High-Yield Pearls for Lichen Planus:** * **6 P’s:** Planar, Purple, Polygonal, Pruritic, Papules, and Plaques. * **Wickham Striae:** White reticular lines on the surface of lesions (due to focal hypergranulosis). * **Max-Joseph Spaces:** Small clefts between the epidermis and dermis due to extensive basal cell degeneration. * **Saw-tooth Rete Ridges:** Characteristic appearance of the epidermal-dermal junction. * **Koebner Phenomenon:** Development of lesions at sites of trauma (also seen in Psoriasis and Vitiligo).

Question 3: The "Hanging Curtain Sign" is characteristic of which dermatological condition?

A. Hordeolum externum
B. Psoriasis
C. Lichen Planus
D. Pityriasis Rosea (Correct Answer)

Explanation: **Explanation:** The **Hanging Curtain Sign** is a classic clinical feature of **Pityriasis Rosea (PR)**. It is elicited by stretching the skin across the long axis of a herald patch or a secondary lesion. Due to the fine, "cigarette paper" like scaling and the way the scales are attached at the periphery (collarette scaling), the scales fold and hang down like a curtain when the skin is pinched or stretched. **Analysis of Options:** * **Pityriasis Rosea (Correct):** An acute, self-limiting inflammatory dermatosis. It typically begins with a **Herald Patch** (a single, large, erythematous scaly plaque) followed by a generalized eruption in a **"Christmas Tree" distribution** along the lines of cleavage (Langer’s lines). * **Psoriasis:** Characterized by the **Auspitz Sign** (pinpoint bleeding upon removal of scales) and **Grattage Test**. The scales are silvery-white and micaceous, not "curtain-like." * **Lichen Planus:** Known for the **6 P’s** (Planar, Purple, Polygonal, Pruritic, Papules, and Plaques) and **Wickham Striae**. It does not exhibit the hanging curtain sign. * **Hordeolum Externum:** This is an acute focal infection (usually Staphylococcal) of the eyelash follicle or associated glands (Zeis/Moll). It is an ophthalmological condition presenting as a painful eyelid bump, unrelated to scaly dermatoses. **High-Yield Clinical Pearls for NEET-PG:** * **Collarette of scales:** Scales in PR are attached at the periphery with free central edges. * **Herald Patch:** The initial lesion seen in 50-90% of cases. * **Etiology:** Associated with **HHV-6 and HHV-7** reactivation. * **Treatment:** Usually self-limiting (6-8 weeks); symptomatic relief with antihistamines or topical steroids.

Question 4: A 'herald patch' is characteristic of which of the following conditions?

A. Pityriasis rosea (Correct Answer)
B. Pityriasis rubra pilaris
C. Pityriasis lichenoides et varioliformis acuta
D. Pityriasis alba

Explanation: ### Explanation **Correct Option: A. Pityriasis rosea** The **Herald Patch** (also known as the "mother patch") is the pathognomonic initial lesion of Pityriasis rosea. It is a single, large (2–6 cm), oval, erythematous, scaly plaque, typically appearing on the trunk. About 1–2 weeks later, a secondary eruption of smaller, similar-looking lesions follows, distributed along the lines of cleavage (Langer’s lines), creating the classic **"Christmas Tree" appearance**. The scales in Pityriasis rosea are characteristically attached at the periphery with a free central edge, known as **collarette scaling**. **Incorrect Options:** * **B. Pityriasis rubra pilaris (PRP):** Characterized by follicular papules on an erythematous base, "islands of sparing" (normal skin within affected areas), and orange-red palmoplantar keratoderma. * **C. Pityriasis lichenoides et varioliformis acuta (PLEVA):** Presents as a sudden eruption of polymorphous papules that undergo necrosis, crusting, and scarring (varioliform scars). * **D. Pityriasis alba:** A common, mild form of dermatitis seen in children (often associated with atopy), presenting as ill-defined hypopigmented patches with fine scaling, usually on the face. **High-Yield Clinical Pearls for NEET-PG:** * **Etiology:** Likely associated with **HHV-6 and HHV-7** reactivation. * **Distribution:** "Christmas tree" or "Fir tree" pattern on the back. * **Herald Patch Location:** Most commonly found on the trunk (90% of cases). * **Treatment:** Usually self-limiting (6–8 weeks). Pruritus is managed with antihistamines or topical steroids. * **Differential Diagnosis:** Secondary syphilis (always rule out if lesions involve palms and soles).

Question 5: What is the most common cause of psoriasis?

A. Autoimmune (Correct Answer)
B. Hereditary
C. Psychosomatic
D. Infective

Explanation: **Explanation:** Psoriasis is fundamentally defined as a **chronic, T-cell mediated autoimmune inflammatory dermatosis**. The core pathophysiology involves the activation of the **IL-23/Th17 axis**, where dendritic cells and T-lymphocytes (specifically Th1 and Th17) release cytokines like TNF-α, IL-17, and IL-22. This "cytokine storm" triggers the rapid, uncontrolled proliferation of keratinocytes, leading to the characteristic thickened, scaly plaques. **Analysis of Options:** * **A. Autoimmune (Correct):** While the exact trigger is often unknown, the disease is driven by an aberrant immune response against self-antigens (like LL-37 or ADAMTSL5) in the skin. * **B. Hereditary:** Genetics play a significant role (e.g., **HLA-Cw6** is the strongest association), but it is considered a predisposing factor rather than the direct "cause." Not everyone with the gene develops the disease. * **C. Psychosomatic:** Stress is a well-known **trigger** or exacerbating factor for flares, but it does not cause the underlying pathology. * **D. Infective:** Certain infections (like Streptococcal pharyngitis) can trigger **Guttate psoriasis**, but the disease itself is not contagious or primarily infectious. **NEET-PG High-Yield Pearls:** * **Auspitz Sign:** Pinpoint bleeding after scraping a scale (due to thinning of suprapapillary epidermis). * **Koebner Phenomenon:** Development of lesions at sites of trauma (also seen in Vitiligo and Lichen Planus). * **Histology:** Look for **Munro’s microabscesses** (neutrophils in the stratum corneum) and **Kogoj’s pustules** (neutrophils in the stratum spinosum). * **Drug Triggers:** Beta-blockers, Lithium, Antimalarials, and NSAIDs (Mnemonic: **BLANS**).

Question 6: Which of the following drugs is NOT used in the management of psoriasis?

A. Psoralens
B. Chloroquine (Correct Answer)
C. Methotrexate
D. Coaltar

Explanation: In the management of psoriasis, the goal is to inhibit keratinocyte proliferation and modulate the immune response. **Why Chloroquine is the correct answer:** Chloroquine (and Hydroxychloroquine) is an antimalarial drug that is notoriously known to **exacerbate or trigger psoriasis**. It can induce a flare-up of stable plaque psoriasis or even precipitate a life-threatening **erythrodermic or pustular transformation**. The mechanism is thought to involve the inhibition of the enzyme transglutaminase and the stimulation of interleukin-8, leading to epidermal hyperproliferation. Therefore, it is strictly avoided in psoriatic patients. **Why the other options are incorrect:** * **Psoralens (Option A):** These are photosensitizing agents used in **PUVA (Psoralen + UVA)** therapy. They intercalate into DNA to inhibit rapid cell division. * **Methotrexate (Option C):** A folic acid antagonist that acts as a potent immunosuppressant and cytotoxin. It is a **gold standard systemic treatment** for severe plaque psoriasis, psoriatic arthritis, and erythrodermic psoriasis. * **Coal Tar (Option D):** One of the oldest topical treatments (e.g., Goeckerman regimen). It has anti-inflammatory and keratoplastic properties that help normalize keratinization. **NEET-PG High-Yield Pearls:** * **Drugs that aggravate psoriasis (mnemonic: B-L-A-C-K):** **B**eta-blockers, **L**ithium, **A**ntimalarials (Chloroquine), **C**orticosteroids (withdrawal), and **K** (Potassium) sparing diuretics/NSAIDs. * **First-line for localized psoriasis:** Topical Vitamin D3 analogues (Calcipotriol) and Corticosteroids. * **Drug of choice for Psoriatic Arthritis:** Methotrexate (though biologics like Secukinumab are increasingly used).

Question 7: A 24-year-old lady with a past history of psoriasis presents with fever and multiple pustular lesions in a generalized distribution. What is the drug of choice for managing her condition?

A. Corticosteroids
B. Retinoids
C. Methotrexate (Correct Answer)
D. Psoralen with PUVA

Explanation: ### **Explanation** The clinical presentation of fever and generalized pustular lesions in a patient with a history of psoriasis is diagnostic of **Generalized Pustular Psoriasis (Von Zumbusch Psoriasis)**. This is a dermatological emergency characterized by sterile pustules on an erythematous base, often triggered by the withdrawal of systemic steroids, infections, or pregnancy. **1. Why Methotrexate is the Correct Answer:** Methotrexate is considered the **first-line systemic treatment** for Generalized Pustular Psoriasis (GPP) in non-pregnant adults. It works by inhibiting dihydrofolate reductase, thereby reducing the rapid epidermal cell turnover and exerting a potent anti-inflammatory effect. It is highly effective in achieving rapid clearance of pustules and stabilizing the patient's systemic symptoms. **2. Analysis of Incorrect Options:** * **Corticosteroids (Option A):** While they may provide temporary relief, systemic steroids are generally **avoided** in psoriasis. Their withdrawal is the most common trigger for precipitating a life-threatening pustular flare (rebound phenomenon). * **Retinoids (Option B):** Oral retinoids (like Acitretin) are highly effective for GPP and are often considered a first-line choice. However, in the context of a **24-year-old lady** (reproductive age), they are avoided due to their significant **teratogenic potential** and long half-life (requiring contraception for 3 years post-treatment). * **PUVA (Option D):** Phototherapy is contraindicated in the acute phase of GPP as it can worsen the inflammatory state and is impractical for a patient with systemic symptoms like fever. **3. NEET-PG High-Yield Pearls:** * **Histopathology:** Look for **Kogoj’s spongiform pustules** (neutrophils in the stratum spinosum) and **Munro’s microabscesses** (neutrophils in the stratum corneum). * **Trigger:** Most common trigger for GPP is the **withdrawal of systemic steroids**. * **Emergency Management:** Always monitor for complications like secondary infections, electrolyte imbalance (hypocalcemia), and high-output heart failure. * **Alternative:** In modern practice, biologicals (like **Infliximab** or **Secukinumab**) are increasingly used for rapid control.

Question 8: Which among the following is the most common site affected by psoriasis?

A. Flexor surface
B. Extensor surface (Correct Answer)
C. Palms and soles
D. Oral mucosa

Explanation: **Explanation:** Psoriasis is a chronic, immune-mediated inflammatory skin disorder characterized by well-demarcated erythematous plaques with silvery-white scales. **Why Extensor Surfaces are Correct:** The hallmark of chronic plaque psoriasis (the most common clinical variant) is its predilection for **extensor surfaces**. The most frequently involved sites are the **elbows, knees, and the scalp**. This distribution is attributed to the **Koebner phenomenon**, where skin lesions appear at sites of repetitive minor trauma or friction, which occurs more frequently on extensor surfaces. **Analysis of Incorrect Options:** * **Flexor surfaces:** Involvement of flexural areas (axilla, groin, submammary folds) is known as **Inverse Psoriasis**. It is less common and characterized by a lack of scaling due to moisture in the skin folds. * **Palms and soles:** While Palmoplantar Psoriasis is a recognized variant, it is significantly less common than the classic plaque type involving extensors. * **Oral mucosa:** Psoriasis rarely involves the oral mucosa. When it does, it may manifest as geographic tongue, but it is never the most common site. **High-Yield Clinical Pearls for NEET-PG:** * **Auspitz Sign:** Pinpoint bleeding upon removal of scales (due to thinning of the suprapapillary plate and dilated capillaries). * **Munro’s Microabscess:** Collection of neutrophils in the stratum corneum (pathognomonic histopathology). * **Grattage Test:** Scraping the lesion increases the visibility of silvery scales (candle grease sign). * **Woronoff’s Ring:** A pale halo of blanched skin surrounding a healing psoriatic plaque.

Question 9: Which of the following conditions produces pre-malignant lesions?

A. Psoriasis
B. Erythema multiforme
C. Lichen planus (Correct Answer)
D. All of the above

Explanation: **Explanation:** The correct answer is **Lichen planus (LP)**. This is because certain variants of Lichen planus, particularly **Oral Lichen Planus (OLP)** and **Vulvar Lichen Planus**, are recognized as **premalignant (potentially malignant) conditions**. Chronic inflammation and rapid cell turnover in these lesions can lead to the development of **Squamous Cell Carcinoma (SCC)**. The risk is highest in the erosive or atrophic subtypes of OLP, with a transformation rate of approximately 0.5% to 2%. **Why other options are incorrect:** * **Psoriasis:** Despite being a chronic inflammatory condition with rapid epidermal hyperplasia, psoriasis is **not** considered a premalignant condition. In fact, some studies suggest a lower incidence of skin cancer within psoriatic plaques themselves, though treatments like PUVA or methotrexate may independently increase malignancy risk. * **Erythema Multiforme:** This is an acute, self-limiting hypersensitivity reaction (often triggered by HSV or drugs). It does not involve chronic tissue remodeling or long-term cellular atypia, and thus carries no risk of malignant transformation. **High-Yield Clinical Pearls for NEET-PG:** * **Lichen Planus:** Characterized by the "6 Ps": Planar, Purple, Polygonal, Pruritic, Papules, and Plaques. Look for **Wickham striae** (white reticular patterns). * **Koebner Phenomenon:** Seen in both Psoriasis and Lichen Planus (development of lesions at sites of trauma). * **Other Premalignant Skin Conditions:** Actinic keratosis (most common), Bowen’s disease, Leukoplakia, and Xeroderma pigmentosum. * **Histopathology of LP:** "Saw-tooth" appearance of rete pegs and basal cell degeneration (liquefaction degeneration).

Question 10: Which of the following is NOT true regarding Munro's microabscess?

A. Seen in the stratum corneum
B. Debris consists of eosinophils (Correct Answer)
C. Associated pustule may be present
D. Seen in psoriasis

Explanation: ### Explanation **Munro’s microabscess** is a hallmark histopathological feature of **Psoriasis**. **1. Why Option B is the correct answer (The False Statement):** Munro’s microabscesses consist of collections of **neutrophils**, not eosinophils. In psoriasis, there is a chemotactic drive (mediated by IL-8 and LTB4) that causes neutrophils to migrate from the papillary capillaries through the epidermis (Kogoj’s spongiform pustules) to the **stratum corneum**, where they form these microabscesses. Eosinophils are typically absent in classic psoriasis; their presence should prompt a search for other diagnoses like drug-induced psoriasiform eruptions. **2. Analysis of Incorrect Options (True Statements):** * **Option A (Seen in the stratum corneum):** This is the characteristic location. As neutrophils migrate upward, they get trapped within the parakeratotic scales of the cornified layer. * **Option C (Associated pustule may be present):** When these neutrophil collections become large and clinically visible, they are termed **Kogoj’s spongiform pustules** (seen in the stratum spinosum) or macro-pustules, as seen in Pustular Psoriasis. * **Option D (Seen in psoriasis):** It is one of the "cardinal" histopathological signs of Psoriasis Vulgaris. **3. High-Yield Clinical Pearls for NEET-PG:** * **Kogoj’s Spongiform Pustule:** Neutrophils in the **stratum spinosum** (multilocular). * **Munro’s Microabscess:** Neutrophils in the **stratum corneum**. * **Other Histopathology features of Psoriasis:** * **Acanthosis:** Thickening of the stratum spinosum with regular elongation of rete ridges ("Camel foot" appearance). * **Parakeratosis:** Retention of nuclei in the stratum corneum. * **Agranulosis:** Thinning or absence of the stratum granulosum. * **Auspitz Sign:** Pinpoint bleeding on scraping the scale due to thinning of the suprapapillary plate and dilated capillaries.

Question 11: Which of the following conditions is characterized by the term 'Acanthosis nigricans'?

A. Dermatomyositis
B. Psoriasis (Correct Answer)
C. Systemic Lupus Erythematosus (SLE)
D. Tinea versicolor

Explanation: **Explanation:** The term **Acanthosis** refers to the diffuse hyperplasia (thickening) of the stratum spinosum layer of the epidermis. In **Psoriasis**, this is a hallmark histopathological feature. Specifically, Psoriasis exhibits **regular elongation of rete ridges** (often described as "test-tube in a rack" appearance) due to the rapid turnover of keratinocytes. **Analysis of Options:** * **Psoriasis (Correct):** The histopathology is characterized by the triad of **Acanthosis**, **Parakeratosis** (retention of nuclei in the stratum corneum), and **Munro’s microabscesses** (neutrophils in the parakeratotic stratum corneum). * **Dermatomyositis:** Characterized by interface dermatitis, vacuolar degeneration of the basal layer, and dermal mucin. Clinical hallmarks include Gottron papules and Heliotrope rash. * **Systemic Lupus Erythematosus (SLE):** Shows liquefactive degeneration of the basal cell layer and follicular plugging, but not the regular acanthosis seen in psoriasis. * **Tinea versicolor:** A fungal infection (Malassezia) characterized by "spaghetti and meatballs" appearance on KOH mount; histopathology shows minimal epidermal change, primarily hyphae and spores in the stratum corneum. **High-Yield Clinical Pearls for NEET-PG:** * **Acanthosis Nigricans vs. Acanthosis:** Do not confuse "Acanthosis" (a histological term) with "Acanthosis Nigricans" (a clinical condition of hyperpigmented velvety plaques associated with insulin resistance or malignancy). * **Auspitz Sign:** Pinpoint bleeding when psoriasis scales are removed, due to thinning of the suprapapillary plate over dilated capillaries. * **Kogoj’s Pustule:** Neutrophils in the stratum spinosum (seen in pustular psoriasis). * **Grattage Test:** Scraping psoriasis lesions produces a candle-grease-like scale.

Question 12: What is the definitive indication for systemic steroids in psoriasis?

A. Pustular psoriasis
B. Erythroderma
C. Psoriatic arthropathy
D. Impetigo herpetiformis (Correct Answer)

Explanation: ### Explanation **Correct Answer: D. Impetigo herpetiformis** **Why it is correct:** Impetigo herpetiformis is a rare, life-threatening variant of **pustular psoriasis occurring during pregnancy** (usually in the third trimester). It is considered a medical emergency due to risks of placental insufficiency, fetal demise, and maternal complications like hypocalcemia or sepsis. While systemic steroids are generally avoided in psoriasis, they are the **first-line systemic treatment** in this specific condition to rapidly control inflammation and protect both the mother and the fetus. **Why the other options are incorrect:** * **A & B (Pustular Psoriasis and Erythroderma):** Systemic steroids are strictly **contraindicated** in these conditions. Although they provide rapid initial clearance, their withdrawal frequently triggers a rebound flare-up, often transforming stable plaque psoriasis into life-threatening generalized pustular psoriasis (Von Zumbusch type). * **C (Psoriatic Arthropathy):** The mainstay of treatment for psoriatic arthritis includes NSAIDs and DMARDs (like Methotrexate or Leflunomide) and biologics (TNF-alpha inhibitors). Systemic steroids are not the definitive treatment and are avoided to prevent skin flares. **High-Yield Clinical Pearls for NEET-PG:** * **The "Steroid Rule":** In dermatology, psoriasis is the classic example where systemic steroids are avoided (except in Impetigo herpetiformis). * **Auspitz Sign:** Pinpoint bleeding on peeling a scale (absent in pustular/erythrodermic variants). * **Woronoff Ring:** A pale halo around a healing psoriasis plaque. * **Drug of Choice for Pustular Psoriasis:** Oral Retinoids (Acitretin) are preferred, but they are strictly contraindicated in pregnancy (teratogenic). This is why steroids are used for Impetigo herpetiformis instead.

Question 13: The Berkley membrane is a characteristic finding in which of the following cutaneous conditions?

A. Psoriasis (Correct Answer)
B. Pemphigus
C. Tinea capitis
D. Pityriasis rubra

Explanation: **Explanation:** The **Berkley membrane** (also known as the "Bulkley membrane") is a classic clinical sign of **Psoriasis**. It refers to the thin, moist, glistening, and transparent membrane that is revealed when the silvery-white scales of a psoriatic plaque are scraped away. **Why Psoriasis is correct:** In Psoriasis, there is marked parakeratosis (retention of nuclei in the stratum corneum). When these scales are removed during the **Auspitz sign** maneuver (Grattage test), the last layer encountered is the thin, translucent Berkley membrane. This membrane represents the stretched-out **stratum lucidum** or the uppermost layer of the viable epidermis. Further scraping of this membrane results in pinpoint bleeding (Auspitz sign) due to the rupture of dilated capillaries in the elongated dermal papillae. **Why other options are incorrect:** * **Pemphigus:** Characterized by intraepidermal blistering due to acantholysis (loss of cell-to-cell adhesion). Key signs include the **Nikolsky sign** and **Asboe-Hansen sign**, not membrane formation. * **Tinea capitis:** A fungal infection of the scalp presenting with hair loss and scaling. Diagnosis involves KOH mount or Wood’s lamp; it does not exhibit the Berkley membrane. * **Pityriasis rubra pilaris (PRP):** While it presents with follicular papules and "islands of sparing," it lacks the specific vascular and epidermal architecture that produces the Berkley membrane and Auspitz sign. **NEET-PG Clinical Pearls:** * **Grattage Test:** The process of scraping psoriatic scales to elicit signs. * **Auspitz Sign:** Pinpoint bleeding after removing the Berkley membrane. It is absent in inverse psoriasis and pustular psoriasis. * **Woronoff’s Ring:** A pale halo around a healing psoriatic plaque. * **Koebner Phenomenon:** Appearance of new lesions at sites of trauma (also seen in Vitiligo and Lichen Planus).

Question 14: What is the best treatment option for psoriasis during pregnancy?

A. Systemic cyclosporine
B. Topical steroids (Correct Answer)
C. PUVA therapy
D. Infliximab

Explanation: **Explanation:** The management of psoriasis in pregnancy follows a "step-up" approach, prioritizing fetal safety while maintaining maternal skin health. **Why Topical Steroids are the Correct Answer:** Topical corticosteroids (low to moderate potency) are considered the **first-line treatment** for psoriasis in pregnancy. They have a well-established safety profile with minimal systemic absorption when used appropriately. If topical steroids alone are insufficient, narrowband UVB (NBUVB) phototherapy is the preferred second-line intervention. **Analysis of Incorrect Options:** * **Systemic Cyclosporine:** While it can be used in severe, refractory cases under strict supervision, it is not the first-line choice due to risks of maternal hypertension, renal toxicity, and potential low birth weight. * **PUVA Therapy:** Psoralen is **contraindicated** in pregnancy because it is mutagenic and teratogenic. While UVA itself is less concerning, the systemic psoralen makes this modality unsafe. * **Infliximab:** Although some biologics are used in pregnancy (especially in the first two trimesters), they are generally reserved for severe cases where first-line therapies fail. They are not the "best" or initial option. **High-Yield Clinical Pearls for NEET-PG:** * **Teratogenic Alert:** **Methotrexate** and **Oral Retinoids (Acitretin)** are strictly contraindicated. Acitretin requires a washout period of 3 years before conception. * **Disease Course:** Approximately 40-60% of patients see improvement in psoriasis during pregnancy due to high progesterone levels, though postpartum flares are common. * **Safe Systemic Option:** If a systemic agent is absolutely necessary, **Cyclosporine** is generally preferred over others, but only after topical and NBUVB options are exhausted.

Question 15: Munro microabscesses are seen in which of the following conditions?

A. Lichen planus
B. Mycosis fungoides
C. Psoriasis (Correct Answer)
D. Eczema

Explanation: ### Explanation **Psoriasis** is a chronic inflammatory dermatosis characterized by epidermal hyperproliferation. The hallmark histopathological feature of psoriasis is the migration of neutrophils from the papillary dermis into the epidermis. * **Munro Microabscesses:** These are collections of **neutrophils** within the **stratum corneum** (parakeratotic layer). They are a pathognomonic finding in psoriasis. * **Kogoj’s Pustules:** Similarly, when neutrophils aggregate in the **stratum spinosum** (malpighian layer), they are termed "Spongiform pustules of Kogoj." #### Why the other options are incorrect: * **Lichen Planus:** Characterized by a "saw-tooth" appearance of rete ridges and **Civatte bodies** (apoptotic keratinocytes), but not neutrophil abscesses. * **Mycosis Fungoides:** A cutaneous T-cell lymphoma characterized by **Pautrier’s microabscesses**, which are collections of atypical T-lymphocytes (mononuclear cells) in the epidermis, not neutrophils. * **Eczema:** Primarily shows **spongiosis** (intercellular edema) and intraepidermal vesicles containing serum and inflammatory cells, but does not typically form Munro microabscesses. #### NEET-PG High-Yield Pearls: 1. **Auspitz Sign:** Pinpoint bleeding when psoriasis scales are removed due to thinning of the suprapapillary plate and dilated capillaries. 2. **Grattage Test:** Scraping the lesion increases the silvery-white scale (candle grease sign). 3. **Woronoff’s Ring:** A pale halo around a healing psoriatic plaque. 4. **Histology Mnemonic:** "Regular elongation of rete ridges" (test-tube in a rack appearance) is classic for Psoriasis.

Question 16: Which of the following histological features are associated with psoriasis?

A. Munro's micro-abscesses, fir tree appearance, and epidermal hyperplasia
B. Munro's micro-abscesses, parakeratosis, and epidermal hyperplasia (Correct Answer)
C. Munro's micro-abscesses, satellite pustules, and epidermal hyperplasia
D. Munro's micro-abscesses, Wickham's striae, and epidermal hyperplasia

Explanation: Psoriasis is a chronic inflammatory dermatosis characterized by accelerated keratinocyte turnover. The histological hallmark of psoriasis is the "psoriatic triad": **epidermal hyperplasia** (regular elongation of rete ridges), **parakeratosis** (retention of nuclei in the stratum corneum), and neutrophilic infiltration. **Why Option B is Correct:** * **Munro’s micro-abscesses:** These are collections of neutrophils within the parakeratotic stratum corneum. (Note: Neutrophils in the stratum spinosum are called *Kogoj’s spongiform pustules*). * **Parakeratosis:** Due to rapid cell division, keratinocytes do not have time to lose their nuclei before reaching the surface. * **Epidermal Hyperplasia:** Specifically "regular" acanthosis, often described as a "test-tube in a rack" appearance. **Analysis of Incorrect Options:** * **Option A:** "Fir tree appearance" is the clinical distribution pattern of **Pityriasis Rosea**, not a histological feature of psoriasis. * **Option C:** "Satellite pustules" are a clinical hallmark of **Candidiasis**, typically found in intertriginous areas. * **Option D:** "Wickham’s striae" are the white, reticulate lines seen clinically in **Lichen Planus**. **High-Yield NEET-PG Pearls:** * **Auspitz Sign:** Pinpoint bleeding when a scale is removed, caused by thinning of the suprapapillary epidermis over dilated capillaries. * **Grattage Test:** Scraping the lesion increases the silvery-white scale (candle grease sign). * **Koebner Phenomenon:** Development of lesions at sites of trauma (also seen in Lichen Planus and Vitiligo). * **Key Histology Mnemonic:** "PMN" – **P**arakeratosis, **M**unro’s micro-abscesses, **N**eutrophils (Kogoj).

Question 17: Von Zumbusch disease is characterized by which of the following manifestations?

A. Pustular psoriasis (Correct Answer)
B. Plaque psoriasis
C. Psoriatic erythroderma
D. Psoriatic arthritis

Explanation: **Explanation:** **Von Zumbusch disease** is the acute, generalized form of **Pustular Psoriasis**. It is a severe, potentially life-threatening variant characterized by the sudden onset of widespread erythema followed by the eruption of numerous sterile, pin-head-sized pustules. These pustules often coalesce to form "lakes of pus." **Why the correct answer is right:** The underlying pathophysiology involves an intense inflammatory response, often triggered by the withdrawal of systemic steroids, infections, or pregnancy (Impetigo Herpetiformis). Clinically, patients present with systemic symptoms like high-grade fever, malaise, and leukocytosis, alongside the characteristic pustular rash. **Analysis of incorrect options:** * **Plaque Psoriasis (Psoriasis Vulgaris):** This is the most common form, characterized by well-demarcated erythematous plaques with silvery-white scaling (Auspitz sign positive), but it does not feature primary pustulation. * **Psoriatic Erythroderma:** This involves >90% of the body surface area becoming red and scaly. While Von Zumbusch can progress to erythroderma, the specific eponym refers to the pustular phase. * **Psoriatic Arthritis:** This is an inflammatory joint disease associated with psoriasis (found in ~30% of patients), typically involving the distal interphalangeal joints and presenting with "pencil-in-cup" deformity on X-ray. **High-Yield Clinical Pearls for NEET-PG:** * **Histopathology:** Look for **Kogoj’s spongiform pustules** (neutrophils in the stratum spinosum) and **Munro’s microabscesses** (neutrophils in the stratum corneum). * **Triggers:** Rapid tapering of systemic corticosteroids is the classic "textbook" trigger for a Von Zumbusch flare. * **Treatment:** Oral Retinoids (Acitretin) are considered the first-line systemic treatment for pustular psoriasis, unlike plaque psoriasis where they are second-line.

Question 18: Oral lesions are not seen in which of the following conditions?

A. Psoriasis (Correct Answer)
B. Pemphigoid
C. Stevens-Johnson syndrome
D. Candidiasis

Explanation: **Explanation:** The correct answer is **Psoriasis**. While psoriasis is a chronic inflammatory dermatosis that can affect the skin, nails, and joints, **oral involvement is extremely rare** and clinically insignificant. When oral lesions are reported (such as "geographic tongue"), they are often considered associated conditions rather than direct psoriatic manifestations. **Analysis of Options:** * **Pemphigoid (Bullous Pemphigoid):** While primarily a subepidermal blistering disease of the skin, oral mucosal involvement occurs in approximately 10–20% of cases (though less frequent than in Pemphigus Vulgaris). Cicatricial pemphigoid specifically targets mucous membranes. * **Stevens-Johnson Syndrome (SJS):** This is a hypersensitivity reaction characterized by extensive mucosal involvement. Hemorrhagic crusting of the lips and painful oral erosions are hallmark features. * **Candidiasis:** This is a fungal infection caused by *Candida albicans*. Oral candidiasis (thrush) is one of the most common clinical presentations, manifesting as white, curd-like plaques. **High-Yield Clinical Pearls for Psoriasis:** * **Auspitz Sign:** Pinpoint bleeding on peeling a scale (due to thinning of the suprapapillary epidermis). * **Koebner Phenomenon:** Development of lesions at sites of trauma (also seen in Vitiligo and Lichen Planus). * **Histology:** Look for **Munro’s microabscesses** (neutrophils in the stratum corneum) and **Kogoj’s pustules** (neutrophils in the stratum spinosum). * **Nail Changes:** Pitting (most common), Oil drop sign (pathognomonic), and subungual hyperkeratosis.

Question 19: What is the primary indication for corticosteroid use in pustular psoriasis?

A. Psoriatic erythroderma during pregnancy (Correct Answer)
B. Psoriasis in a patient with alcoholic cirrhosis
C. Moderate arthritis
D. Extensive lesions

Explanation: ### Explanation **Correct Option: A. Psoriatic erythroderma during pregnancy** The primary indication for systemic corticosteroids in psoriasis is extremely limited due to the risk of triggering a life-threatening rebound flare of **Generalized Pustular Psoriasis (von Zumbusch)** upon withdrawal. However, **Impetigo Herpetiformis** (a variant of pustular psoriasis occurring in pregnancy) and associated psoriatic erythroderma represent a critical exception. In pregnancy, first-line systemic retinoids (Acitretin) and Methotrexate are strictly **teratogenic** and contraindicated. Therefore, systemic steroids are used as a rescue therapy to manage severe systemic inflammation and protect both maternal and fetal well-being. **Why the other options are incorrect:** * **B. Alcoholic Cirrhosis:** While Methotrexate is contraindicated in cirrhosis, the preferred alternative is usually **Acitretin** or biologics. Steroids are avoided to prevent pustular flares. * **C. Moderate Arthritis:** The standard of care for psoriatic arthritis includes NSAIDs and DMARDs (Methotrexate, Leflunomide, or TNF-alpha inhibitors). Systemic steroids are not a primary treatment for joint involvement in psoriasis. * **D. Extensive Lesions:** For extensive plaque psoriasis, the treatment of choice is **Phototherapy (NBUVB)** or systemic agents like Methotrexate/Cyclosporine. Using steroids here is a classic "contraindication" because it leads to unstable disease. **High-Yield Clinical Pearls for NEET-PG:** * **The "Steroid Rule":** Never use systemic steroids for routine plaque psoriasis. It is the most common trigger for **Generalized Pustular Psoriasis**. * **Impetigo Herpetiformis:** Usually occurs in the 3rd trimester; associated with hypocalcemia. Treatment: Systemic steroids + Cyclosporine (if refractory). * **Drug of Choice (DOC):** For Generalized Pustular Psoriasis (non-pregnant), the DOC is **Acitretin**. For Psoriatic Arthritis, the DOC is **Methotrexate**.

Question 20: A herald patch is a characteristic finding in which dermatological condition?

A. Pityriasis rosea (Correct Answer)
B. Lichen planus
C. Pityriasis alba
D. Tinea versicolor

Explanation: **Explanation:** The **Herald Patch** is the pathognomonic initial lesion of **Pityriasis Rosea (PR)**, a self-limiting inflammatory skin disease likely triggered by HHV-6 or HHV-7. It typically presents as a single, large (2–6 cm), oval, salmon-colored or erythematous plaque with a peripheral "collarette" of scale. Following this by 1–2 weeks, a generalized eruption occurs along skin tension lines, creating the classic **"Christmas Tree" appearance** on the back. **Analysis of Incorrect Options:** * **Lichen Planus:** Characterized by the "6 Ps" (Planar, Purple, Polygonal, Pruritic, Papules, and Plaques). It features **Wickham striae** (white reticular patterns) rather than a herald patch. * **Pityriasis Alba:** A manifestation of atopic dermatitis presenting as hypopigmented, ill-defined patches with fine scaling, most commonly on the faces of children. * **Tinea Versicolor:** Caused by *Malassezia furfur*, presenting as hypo- or hyperpigmented macules with fine dust-like scales (branny desquamation). Diagnosis is confirmed by a "spaghetti and meatballs" appearance on KOH mount. **High-Yield Clinical Pearls for NEET-PG:** * **Collarette of Scale:** In PR, the scale is attached peripherally and directed inwards. * **Distribution:** PR follows **Langer’s lines** (cleavage lines). * **Differential Diagnosis:** Secondary syphilis can mimic PR but typically involves the palms and soles (which PR spares) and presents with lymphadenopathy. * **Treatment:** PR is usually self-limiting (6–8 weeks); treatment is symptomatic (antihistamines/topical steroids).

Question 21: Monro's abscesses are seen in which of the following conditions?

A. Pemphigus
B. Lichen planus
C. Leukoplakia
D. Psoriasis (Correct Answer)

Explanation: **Explanation:** **Monro’s microabscesses** are a hallmark histopathological feature of **Psoriasis**. They consist of small collections of **neutrophils** within the **stratum corneum** (horny layer). This occurs due to the rapid migration of neutrophils from the papillary dermis through the epidermis, driven by chemotactic factors like IL-8 and LTB4. **Analysis of Options:** * **Psoriasis (Correct):** Along with Monro’s microabscesses, psoriasis is characterized by **Kogoj’s pustules** (neutrophils in the stratum spinosum), parakeratosis (nuclei in the stratum corneum), and regular elongation of rete ridges. * **Pemphigus:** This is an autoimmune blistering disorder characterized by **acantholysis** (loss of cell-to-cell adhesion) and intraepidermal blisters. * **Lichen Planus:** Histology shows a "saw-tooth" appearance of rete ridges, **Wickham striae**, and a band-like lymphocytic infiltrate at the dermo-epidermal junction (Civatte bodies). * **Leukoplakia:** This is a clinical term for a white patch; histologically, it shows hyperkeratosis and varying degrees of epithelial dysplasia, but not neutrophilic abscesses. **High-Yield Clinical Pearls for NEET-PG:** * **Auspitz Sign:** Pinpoint bleeding on scraping a psoriatic plaque due to thinning of the suprapapillary plate. * **Grattage Test:** Scraping the lesion increases the silvery-white scale (candle grease sign). * **Koebner Phenomenon:** Development of new lesions at sites of trauma (also seen in Lichen Planus and Vitiligo). * **Histology Mnemonic:** "Munro is on top (Corneum), Kogoj is below (Spinosum)."

Question 22: What is the primary treatment for pustular psoriasis?

A. Thalidomide
B. Retinoids (Correct Answer)
C. Hydroxyurea
D. Methotrexate

Explanation: **Explanation:** **Pustular Psoriasis** (von Zumbusch type) is a severe, systemic form of psoriasis characterized by widespread sterile pustules on an erythematous base. The primary goal of treatment is rapid control of inflammation and stabilization of the skin barrier. **Why Retinoids are the Correct Answer:** Oral retinoids, specifically **Acitretin**, are considered the first-line treatment (drug of choice) for generalized pustular psoriasis. Retinoids work by modulating keratinocyte proliferation and differentiation and, crucially, exert a potent **anti-inflammatory effect** by inhibiting neutrophil chemotaxis into the epidermis (which forms the pustules). Their rapid onset of action in controlling pustulation makes them superior in this clinical subtype. **Analysis of Incorrect Options:** * **Thalidomide (A):** While it has anti-TNF properties, it is not a standard or first-line treatment for psoriasis due to its severe teratogenicity and peripheral neuropathy risks. * **Hydroxyurea (C):** This is a second or third-line cytotoxic agent used only when other systemic therapies (like Methotrexate or Cyclosporine) are contraindicated or ineffective. * **Methotrexate (D):** While Methotrexate is the drug of choice for **Chronic Plaque Psoriasis**, it is generally considered second-line for the acute phase of Pustular Psoriasis, as it acts slower than retinoids or cyclosporine. **High-Yield Clinical Pearls for NEET-PG:** * **Histopathology:** Look for the **Kogoj’s spongiform pustule** (neutrophils in the stratum spinosum). * **Triggers:** Sudden withdrawal of systemic steroids is the most common trigger for pustular psoriasis. * **Contraindication:** Avoid Acitretin in females of childbearing age unless strict contraception is used, as it is highly teratogenic (pregnancy must be avoided for 3 years after stopping). * **Alternative:** If a rapid response is needed and retinoids are contraindicated, **Cyclosporine** is the preferred alternative.

Question 23: Which of the following conditions is characterized by "sausage digits"?

A. Lyme disease
B. Osteoarthritis
C. Psoriatic arthritis (Correct Answer)
D. None of the above

Explanation: ### Explanation **Correct Answer: C. Psoriatic arthritis** **1. Why Psoriatic Arthritis is Correct:** The term **"sausage digit"** refers to **Dactylitis**, which is the uniform, generalized swelling of an entire finger or toe. In Psoriatic Arthritis (PsA), this occurs due to a combination of inflammation in the small joints (synovitis) and the surrounding tendons and ligaments (enthesitis/tenosynovitis). Dactylitis is a hallmark feature of Seronegative Spondyloarthropathies (like PsA) and is seen in approximately 30-50% of patients with PsA. It typically affects the digits asymmetrically. **2. Why Other Options are Incorrect:** * **A. Lyme Disease:** Typically presents with a "bull’s eye" rash (Erythema chronicum migrans) and large joint oligoarthritis (most commonly the knee). It does not typically cause diffuse digital swelling (dactylitis). * **B. Osteoarthritis:** Characterized by bony enlargements at specific joints, such as **Heberden’s nodes** (DIP joints) and **Bouchard’s nodes** (PIP joints). The swelling is localized to the joint itself, not the entire digit. **3. NEET-PG High-Yield Clinical Pearls:** * **Pencil-in-cup deformity:** The classic radiographic finding in PsA due to periarticular erosions and bone resorption. * **Nail changes:** Pitting, onycholysis, and subungual hyperkeratosis are strong predictors of joint involvement in psoriasis. * **Auspitz Sign:** Pinpoint bleeding upon removal of a psoriasis scale (due to thinning of the suprapapillary plate). * **Woronoff’s Ring:** A pale halo of blanched skin surrounding a healing psoriatic plaque. * **Other causes of Dactylitis:** Sickle cell disease (Hand-foot syndrome), Sarcoidosis, and Reactive Arthritis.

Question 24: Bleeding spots are seen on removal of of plaques in which of the following conditions?

A. Psoriasis (Correct Answer)
B. Lichen planus
C. Lichen striatus
D. Systemic Lupus Erythematosus (SLE)

Explanation: The correct answer is **Psoriasis**. ### **Explanation** The phenomenon described is the **Auspitz sign**, a hallmark clinical feature of Psoriasis. **Why it occurs:** In Psoriasis, there is significant epidermal hyperplasia (acanthosis) and thinning of the epidermis overlying the dermal papillae (suprapapillary thinning). Additionally, the blood vessels within the dermal papillae become dilated and tortuous. When a psoriatic plaque is forcibly removed or scraped, these fragile, superficial capillaries are ruptured, resulting in **pinpoint bleeding spots**. ### **Analysis of Incorrect Options** * **Lichen planus:** Characterized by the **6 Ps** (Planar, Purple, Polygonal, Pruritic, Papules, and Plaques) and **Wickham striae** (whitish reticular lines). It does not show Auspitz sign. * **Lichen striatus:** A self-limiting linear dermatosis following **Blaschko’s lines**, typically seen in children. It lacks the vascular changes seen in psoriasis. * **Systemic Lupus Erythematosus (SLE):** Cutaneous SLE (like DLE) is characterized by **carpet tacking sign** (follicular plugging seen when a scale is removed), not pinpoint bleeding. ### **NEET-PG High-Yield Pearls** * **Grattage Test:** The clinical procedure of scraping a lesion with a glass slide to elicit the Auspitz sign. * **Koebner Phenomenon:** Development of new psoriatic lesions at sites of trauma (also seen in Lichen Planus and Vitiligo). * **Woronoff Ring:** A pale halo of blanched skin surrounding a healing psoriatic plaque. * **Munro’s Microabscesses:** Collections of neutrophils in the stratum corneum (histopathological hallmark).

Question 25: Berkeley membrane is seen in which of the following conditions?

A. Psoriasis (Correct Answer)
B. Pemphigus
C. Tinea capitis
D. Pityriasis rubra

Explanation: **Explanation:** **Berkeley membrane** (also known as the "Bulkeley membrane") is a classic clinical sign of **Psoriasis**. It refers to the thin, moist, and transparent layer of epidermis that is revealed when the silvery-white scales of a psoriatic plaque are scraped off (Grattage test). 1. **Why Psoriasis is correct:** In Psoriasis, there is marked parakeratosis (retention of nuclei in the stratum corneum) and thinning of the suprapapillary plate. When scales are removed, this thin membrane is exposed. Further scraping of this membrane leads to pinpoint bleeding points, a phenomenon known as the **Auspitz sign**, caused by the rupture of dilated capillaries in the dermal papillae. 2. **Why other options are incorrect:** * **Pemphigus:** Characterized by intraepidermal blistering due to acantholysis (loss of cell-to-cell adhesion). Key signs include the **Nikolsky sign** and **Asboe-Hansen sign**. * **Tinea capitis:** A fungal infection of the scalp. Clinical features include "black dots," "grey patches," or kerion, but it does not involve the Berkeley membrane. * **Pityriasis rubra pilaris (PRP):** Characterized by follicular papules on an erythematous base and "islands of sparing." While it is a papulosquamous disorder like psoriasis, it lacks the Auspitz sign and Berkeley membrane. **High-Yield Clinical Pearls for Psoriasis:** * **Grattage Test:** The process of scraping scales to reveal the Berkeley membrane and Auspitz sign. * **Koebner Phenomenon:** Development of new lesions at sites of trauma (also seen in Vitiligo and Lichen Planus). * **Woronoff Ring:** A pale halo around a healing psoriatic plaque. * **Munro’s Microabscess:** Collection of neutrophils in the stratum corneum (Histopathology). * **Kogoj’s Pustule:** Neutrophils in the stratum spinosum.

Question 26: Psoriasis is characterized by which sign?

A. Darier's sign
B. Auspitz sign (Correct Answer)
C. Nikolsky's sign
D. Gottoson's sign

Explanation: **Explanation:** **Auspitz sign** is a classic clinical hallmark of **Psoriasis**. It refers to the appearance of pinpoint bleeding points when psoriatic scales are forcibly removed. This occurs due to the underlying histopathology of psoriasis: **elongated dermal papillae** (papillomatosis) and the thinning of the suprapapillary epidermis. When the scale is lifted, the dilated and tortuous capillaries within these prominent dermal papillae are ruptured, leading to focal bleeding. **Analysis of Incorrect Options:** * **Darier's sign:** Seen in **Mastocytosis** (specifically Urticaria Pigmentosa). It involves the formation of a wheal and flare after firm stroking of a lesion due to mast cell degranulation and histamine release. * **Nikolsky's sign:** A characteristic of **Pemphigus Vulgaris** and SJS/TEN. It is positive when the top layer of skin slips away from the lower layers when rubbed, indicating acantholysis (loss of intercellular adhesion). * **Gottron’s sign:** (Corrected spelling of "Gottoson's") These are erythematous, scaly papules found over the bony prominences of the knuckles, pathognomonic for **Dermatomyositis**. **High-Yield Clinical Pearls for NEET-PG:** * **Grattage Test:** The procedure of scraping psoriatic lesions with a glass slide to elicit the Auspitz sign. * **Koebner Phenomenon:** Development of new psoriatic lesions at sites of local trauma (also seen in Lichen Planus and Vitiligo). * **Woronoff’s Ring:** A pale halo of blanched skin surrounding a healing psoriatic plaque. * **Histology Mnemonic:** "MUNRO’S microabscesses" (Neutrophils in the stratum corneum) and "KOGOJ’S pustules" (Neutrophils in the stratum spinosum).

Question 27: Which of the following is the drug of choice in the treatment of erythrodermic psoriasis?

A. Psoralen
B. Systemic steroid
C. Methotrexate (Correct Answer)
D. Estrogen

Explanation: **Explanation:** **Erythrodermic Psoriasis** is a severe, life-threatening form of psoriasis characterized by generalized erythema and scaling involving >90% of the body surface area. It requires prompt systemic intervention. **1. Why Methotrexate is the Correct Answer:** Methotrexate is considered the **first-line systemic treatment (Drug of Choice)** for stable erythrodermic psoriasis. It acts as a folic acid antagonist, inhibiting dihydrofolate reductase, which leads to decreased DNA synthesis and potent immunosuppression. It effectively halts the rapid epidermal cell turnover characteristic of this condition. Other first-line options include Cyclosporine (preferred if rapid onset is needed) and Acitretin. **2. Why the Other Options are Incorrect:** * **Psoralen (Option A):** Psoralen combined with UVA (PUVA) is contraindicated in the acute phase of erythrodermic psoriasis. Phototherapy can trigger further irritation and worsen the erythroderma. * **Systemic Steroids (Option B):** These are generally **avoided** in psoriasis. While they may provide temporary relief, their withdrawal often triggers a severe rebound flare or precipitates **von Zumbusch pustular psoriasis**. * **Estrogen (Option C):** Estrogen has no established role in the treatment of psoriasis. **Clinical Pearls for NEET-PG:** * **Most common trigger:** Sudden withdrawal of systemic steroids. * **Complications:** High-output heart failure, hypothermia, and protein loss (hypoalbuminemia) due to excessive scaling. * **Treatment Hierarchy:** * **Methotrexate:** Standard DOC. * **Cyclosporine:** Fastest acting; used in unstable/severe cases. * **Infliximab:** Highly effective biological agent for rapid control. * **Auspitz Sign:** Usually absent in erythrodermic and pustular psoriasis.

Question 28: Which of the following is the most serious type of psoriasis?

A. Chronic plaque psoriasis
B. Generalized pustular psoriasis (Correct Answer)
C. Guttate psoriasis
D. Flexural psoriasis

Explanation: **Explanation:** **Generalized Pustular Psoriasis (Von Zumbusch Psoriasis)** is considered the most serious and life-threatening form of the disease. Unlike chronic plaque psoriasis, it is characterized by the sudden onset of widespread sterile pustules on an erythematous base. The severity arises from systemic involvement; patients often present with high-grade fever, malaise, leukocytosis, and electrolyte imbalances. If left untreated, it can lead to fatal complications such as secondary sepsis, acute respiratory distress syndrome (ARDS), and high-output heart failure. **Analysis of Incorrect Options:** * **Chronic Plaque Psoriasis:** This is the most *common* type (affecting ~90% of patients) but is typically stable and localized to extensor surfaces, posing no immediate threat to life. * **Guttate Psoriasis:** Characterized by small, "drop-like" lesions often triggered by a Streptococcal sore throat. It is usually self-limiting or responds well to phototherapy. * **Flexural (Inverse) Psoriasis:** Occurs in skin folds (axilla, groin). While uncomfortable due to maceration and secondary fungal infections, it lacks systemic toxicity. **High-Yield Clinical Pearls for NEET-PG:** * **Erythrodermic Psoriasis** is the other "dermatological emergency" in the psoriasis spectrum, involving >90% of body surface area. * **Trigger:** Sudden withdrawal of systemic steroids is a classic trigger for Generalized Pustular Psoriasis. * **Histology:** Look for **Kogoj’s spongiform pustules** (neutrophils in the stratum spinosum) and **Munro’s microabscesses** (neutrophils in the stratum corneum). * **Treatment of Choice:** Oral Retinoids (Acitretin) are generally preferred for the pustular variant.

Question 29: A topical retinoid recently introduced for the treatment of psoriasis is:

A. Adapalene
B. Tazarotene (Correct Answer)
C. Alitretinoin
D. Bexarotene

Explanation: **Explanation:** **Tazarotene** is a third-generation topical retinoid specifically approved for the treatment of plaque psoriasis. It works by selectively binding to **retinoic acid receptors (RAR-β and RAR-γ)**. In psoriasis, it normalizes keratinocyte differentiation, inhibits hyperproliferation, and decreases inflammatory markers. It is often used in combination with topical corticosteroids to enhance efficacy and reduce the localized irritation (burning/stinging) commonly associated with its use. **Analysis of Incorrect Options:** * **Adapalene (A):** A third-generation retinoid primarily used for **Acne Vulgaris**. While it has anti-inflammatory properties, it is not a standard or FDA-approved treatment for psoriasis. * **Alitretinoin (C):** A 9-cis-retinoic acid derivative. Its topical form is used for **Kaposi Sarcoma** lesions, and its oral form is highly effective for chronic refractory **hand eczema**. * **Bexarotene (D):** A selective **RXR (Retinoid X Receptor)** ligand. It is specifically used (topically and systemically) for the treatment of **Cutaneous T-cell Lymphoma (CTCL)**, such as Mycosis Fungoides. **High-Yield Clinical Pearls for NEET-PG:** * **Tazarotene** is pregnancy category X (contraindicated) and should not be applied to more than 20% of the body surface area. * **First-line topical therapy** for localized psoriasis remains the combination of a potent corticosteroid and a Vitamin D3 analogue (e.g., **Calcipotriol**). * **Oral Retinoid for Psoriasis:** **Acitretin** is the systemic retinoid of choice, particularly for pustular and erythrodermic variants. Remember: Acitretin requires a 3-year washout period before pregnancy.

Question 30: All of the following are seen in psoriasis except?

A. Auspitz sign present
B. 10% associated with arthritis
C. It is a premalignant disease (Correct Answer)
D. Worsening of disease during winter

Explanation: **Explanation:** Psoriasis is a chronic, immune-mediated inflammatory skin disorder characterized by keratinocyte hyperproliferation. The correct answer is **C** because **Psoriasis is NOT a premalignant disease.** Unlike conditions like Actinic Keratosis or Bowen’s disease, psoriasis does not carry an inherent risk of transforming into malignancy (though long-term treatments like PUVA may slightly increase skin cancer risk). **Analysis of Options:** * **Auspitz Sign (Option A):** This is a classic clinical feature. When silvery scales are removed (Grattage test), pinpoint bleeding occurs due to the thinning of the suprapapillary epidermis and the presence of dilated, tortuous capillaries in the dermal papillae. * **Arthritis (Option B):** Approximately **5–10%** (some texts suggest up to 30%) of patients develop Psoriatic Arthritis. It is typically Seronegative (RF negative) and often involves the distal interphalangeal (DIP) joints. * **Seasonal Variation (Option D):** Psoriasis typically **worsens in winter** due to cold weather and lack of UV light (which has an immunosuppressive effect on the skin). It generally improves in summer. **NEET-PG High-Yield Pearls:** * **Histopathology:** Key features include **Munro’s microabscess** (neutrophils in the stratum corneum) and **Kogoj’s pustule** (neutrophils in the stratum spinosum). * **Koebner Phenomenon:** Development of psoriatic lesions at sites of trauma (also seen in Lichen Planus and Vitiligo). * **Woronoff’s Ring:** A pale halo of blanched skin surrounding a healing psoriatic plaque. * **Nail Changes:** Pitting (most common), Oil spots (most specific), and subungual hyperkeratosis.

Question 31: Which skin condition is characterized by lesions with plaques covered in silvery scales over the back?

A. Lichen planus
B. Psoriasis (Correct Answer)
C. Pemphigus
D. Leprosy

Explanation: **Explanation:** The correct answer is **Psoriasis**. This is a chronic, immune-mediated inflammatory dermatosis characterized by well-demarcated, erythematous (red) plaques covered with characteristic **silvery-white, micaceous scales**. These lesions typically appear on extensor surfaces such as the elbows, knees, and the lower back (lumbosacral region). The scaling occurs due to hyperkeratosis and parakeratosis resulting from an accelerated epidermal cell turnover (shortened from 28 days to about 4 days). **Why other options are incorrect:** * **Lichen Planus:** Characterized by the "6 Ps": Planar (flat-topped), Purple, Polygonal, Pruritic, Papules, and Plaques. It features **Wickham striae** (whitish reticular lines) rather than silvery scales. * **Pemphigus:** An autoimmune blistering disease. It presents with fragile, flaccid bullae and painful erosions on the skin and mucous membranes, not scaly plaques. * **Leprosy:** Tuberculoid leprosy may present with hypopigmented or erythematous plaques, but these are typically associated with **loss of sensation** and absence of hair/sweat, rather than thick silvery scaling. **High-Yield Clinical Pearls for NEET-PG:** * **Auspitz Sign:** Pinpoint bleeding occurs when scales are forcibly removed (due to thinning of the suprapapillary epidermis). * **Koebner Phenomenon:** Development of new lesions at sites of trauma (also seen in Lichen Planus and Vitiligo). * **Histology:** Look for **Munro’s microabscesses** (neutrophils in the stratum corneum) and **Kogoj’s pustules**. * **Nail changes:** Pitting (most common), Oil spots, and Onycholysis.

Question 32: Nails are involved in which of the following conditions?

A. Pemphigus
B. Pemphigoid
C. Psoriasis (Correct Answer)
D. Dermatitis Herpetiformis

Explanation: **Explanation:** **Psoriasis** is a chronic inflammatory dermatosis where nail involvement is highly characteristic, occurring in approximately 50% of patients with cutaneous lesions and up to 80% of those with psoriatic arthritis. The clinical presentation depends on the site of involvement: * **Nail Matrix involvement:** Results in **pitting** (the most common finding), leukonychia, and crumbling of the nail plate. * **Nail Bed involvement:** Results in **"Oil spots" (salmon patches)**, subungual hyperkeratosis, and distal onycholysis. **Why the other options are incorrect:** * **Pemphigus & Pemphigoid:** These are autoimmune bullous disorders primarily affecting the skin and mucous membranes. While severe paronychia or nail shedding (onychomadesis) can rarely occur in Pemphigus Vulgaris due to periungual blistering, it is not a classic or diagnostic feature compared to Psoriasis. * **Dermatitis Herpetiformis (DH):** This is an IgA-mediated immunobullous disease associated with gluten-sensitive enteropathy. It typically presents with intensely pruritic vesicles on extensor surfaces; nail involvement is not a feature of DH. **High-Yield Clinical Pearls for NEET-PG:** * **Pitting in Psoriasis:** Deep, irregular, and randomly distributed (unlike the shallow, regular pits seen in Alopecia Areata). * **Oil Spot Sign:** Pathognomonic for psoriasis; represents focal exocytosis of neutrophils under the nail plate. * **Association:** Nail changes are a strong predictor of future development of **Psoriatic Arthritis** (specifically involving the Distal Interphalangeal joints). * **Differential Diagnosis:** Psoriasis must be differentiated from **Onychomycosis** (fungal infection) using KOH mount or fungal culture.

Question 33: Which type of psoriasis is associated with streptococcal throat infection?

A. Pustular
B. Flexural
C. Guttate (Correct Answer)
D. Scalp

Explanation: **Explanation:** **Guttate Psoriasis** is the correct answer because it is classically triggered by an upper respiratory tract infection, most commonly **Group A Beta-hemolytic Streptococcal (GABHS)** pharyngitis. The term "guttate" is derived from the Latin word *gutta* (drop), reflecting its clinical presentation: sudden onset of small, salmon-pink, drop-like papules with fine scales, primarily on the trunk and proximal extremities. This occurs due to molecular mimicry or a superantigen-mediated immune response following the infection. **Analysis of Incorrect Options:** * **Pustular Psoriasis:** Characterized by sterile pustules on an erythematous base. It is typically triggered by the withdrawal of systemic steroids, pregnancy (Impetigo Herpetiformis), or infections, but it lacks the specific, strong association with Streptococcal throat infections seen in the guttate variety. * **Flexural (Inverse) Psoriasis:** Involves skin folds (axilla, groin, sub-mammary). It presents as smooth, erythematous plaques without scaling. It is not typically associated with an acute post-streptococcal trigger. * **Scalp Psoriasis:** A common site for chronic plaque psoriasis. While it can coexist with other forms, it is not the specific subtype defined by a preceding sore throat. **High-Yield Clinical Pearls for NEET-PG:** * **Latency:** The skin eruption typically appears **1–3 weeks** after the throat infection. * **Diagnosis:** Often shows elevated **ASO (Antistreptolysin O) titers** and positive throat cultures. * **Prognosis:** It has a good prognosis and may resolve spontaneously, though it can progress to chronic plaque psoriasis in about 30-40% of cases. * **Treatment:** Management includes treating the underlying infection (Antibiotics), phototherapy (NB-UVB), and topical steroids.

Question 34: Munro microabscesses are typically seen in which layer of the epidermis?

A. Dermal tissue
B. Stratum basale
C. Stratum corneum (Correct Answer)
D. Stratum malpighi

Explanation: **Explanation:** **Munro microabscesses** are a pathognomonic histological feature of **Psoriasis**. They consist of small collections of **neutrophils** that have migrated from the papillary dermis through the epidermis to become trapped within the **Stratum corneum** (specifically within areas of parakeratosis). This occurs due to the rapid epidermal turnover and chemotactic signals (like IL-8 and LTB4) that draw inflammatory cells upward. **Analysis of Options:** * **Option C (Stratum corneum):** This is the correct anatomical location where these neutrophilic aggregates settle. * **Option A (Dermal tissue):** While the inflammatory process begins here (dilated capillaries in dermal papillae), the term "Munro microabscess" specifically refers to the epidermal collection. * **Option B (Stratum basale):** This is the deepest layer of the epidermis; neutrophils pass through it but do not aggregate here. * **Option D (Stratum malpighi):** This refers to the combined layer of the stratum basale and stratum spinosum. Neutrophilic collections found here are known as **Kogoj’s spongiform pustules**, not Munro microabscesses. **High-Yield NEET-PG Pearls for Psoriasis Histopathology:** 1. **Kogoj’s Spongiform Pustule:** Neutrophils in the **Stratum spinosum** (Malpighian layer). 2. **Auspitz Sign:** Pinpoint bleeding on scraping scales due to thinning of the suprapapillary plate and dilated capillaries. 3. **Other features:** Parakeratosis (nuclei in stratum corneum), Regular elongation of rete ridges (camel-foot appearance), and **absent/diminished Stratum granulosum**. 4. **Key Cytokines:** Driven by the **Th17/Th1 pathway** (IL-17, IL-23, and TNF-α).

Question 35: Munro microabscesses are characteristic findings in which of the following dermatological conditions?

A. Lichen planus
B. Mycosis fungoides
C. Psoriasis (Correct Answer)
D. Eczema

Explanation: **Explanation:** **Munro microabscesses** are a hallmark histopathological feature of **Psoriasis**. They consist of collections of **neutrophils** within the **stratum corneum** (parakeratotic layer). This occurs due to the rapid upward migration of neutrophils from the dermal papillae through the epidermis, driven by chemotactic factors like IL-8 and LTB4. **Analysis of Options:** * **Psoriasis (Correct):** Along with Munro microabscesses, other key findings include **Kogoj’s spongiform pustules** (neutrophils in the stratum spinosum), regular elongation of rete ridges (test-tube appearance), and thinning of the suprapapillary plate. * **Lichen Planus:** Characterized by "saw-tooth" rete ridges, hypergranulosis, and a band-like lymphocytic infiltrate at the dermo-epidermal junction (Civatte bodies), not neutrophilic abscesses. * **Mycosis Fungoides:** A cutaneous T-cell lymphoma characterized by **Pautrier’s microabscesses**, which are clusters of atypical T-lymphocytes (not neutrophils) within the epidermis. * **Eczema:** Primarily shows **spongiosis** (intercellular edema) and a lymphocytic infiltrate. **High-Yield Clinical Pearls for NEET-PG:** * **Auspitz Sign:** Pinpoint bleeding when psoriasis scales are removed (due to thinning of the suprapapillary plate). * **Koebner Phenomenon:** Development of lesions at sites of trauma (also seen in Lichen Planus and Vitiligo). * **Woronoff Ring:** A pale halo around a healing psoriatic plaque. * **Histology Mnemonic:** **M**unro = **M**ultilobed (Neutrophils); **P**autrier = **P**eripheral blood cells (Lymphocytes).

Question 36: Tildrakizumab was approved by the FDA in 2018 for which condition?

A. Cystic fibrosis
B. Migraine
C. Hypertension
D. Psoriasis (Correct Answer)

Explanation: **Explanation:** **Tildrakizumab** is a high-affinity, humanized IgG1 kappa monoclonal antibody that specifically targets the **p19 subunit of Interleukin-23 (IL-23)**. In the pathogenesis of psoriasis, the IL-23/Th17 axis plays a central role; by inhibiting IL-23, Tildrakizumab prevents the release of downstream pro-inflammatory cytokines like IL-17 and IL-22, thereby reducing keratinocyte hyperproliferation and plaque formation. It was FDA-approved in 2018 for the treatment of moderate-to-severe plaque psoriasis in adults who are candidates for systemic therapy or phototherapy. **Analysis of Incorrect Options:** * **Cystic Fibrosis:** Treated with CFTR modulators (e.g., Ivacaftor) and antibiotics, not monoclonal antibodies targeting IL-23. * **Migraine:** Managed with CGRP antagonists (e.g., Erenumab) or triptans. * **Hypertension:** Managed with ACE inhibitors, ARBs, or calcium channel blockers; biologics currently have no role in standard hypertension management. **NEET-PG High-Yield Pearls:** * **Mechanism:** IL-23 inhibitor (p19 subunit). Other drugs in this class include **Guselkumab** and **Risankizumab**. * **Ustekinumab vs. Tildrakizumab:** Ustekinumab targets the **p40 subunit** (shared by IL-12 and IL-23), whereas Tildrakizumab is selective for the **p19 subunit** (specific to IL-23). * **Dosing:** It is administered subcutaneously at weeks 0, 4, and then every 12 weeks, making it a convenient long-term maintenance option. * **Screening:** Always screen for **Latent Tuberculosis (TB)** before initiating any biological therapy for psoriasis.

Question 37: Test tube-shaped rete pegs is a feature of which condition?

A. Psoriasis. (Correct Answer)
B. Reiter's syndrome.
C. Geographic tongue.
D. OSMF.

Explanation: **Explanation:** The correct answer is **Psoriasis**. This question focuses on the classic histopathological features of Psoriasis vulgaris, which are high-yield for NEET-PG. **1. Why Psoriasis is Correct:** In Psoriasis, there is a marked increase in the proliferation of keratinocytes (increased mitotic activity). This leads to **regular elongation of the rete ridges** (the downward projections of the epidermis into the dermis). These elongated ridges appear uniform, thin, and rounded at the base, resembling **"test tubes in a rack."** Other hallmark histopathological features include: * **Parakeratosis:** Retention of nuclei in the stratum corneum. * **Munro’s microabscesses:** Neutrophils within the parakeratotic stratum corneum. * **Kogoj’s spongiform pustules:** Neutrophils in the stratum spinosum. * **Auspitz sign:** Pinpoint bleeding when scales are removed due to thinning of the suprapapillary plate and dilated capillaries. **2. Why other options are incorrect:** * **Reiter’s Syndrome (Reactive Arthritis):** While it can show "psoriasiform" changes (like Munro’s microabscesses), the classic "test tube" description is specifically associated with Psoriasis. * **Geographic Tongue (Benign Migratory Glossitis):** This is considered an oral form of psoriasis and shows similar features, but the question asks for the primary condition where this sign is the diagnostic hallmark. * **OSMF (Oral Submucous Fibrosis):** This is characterized by juxta-epithelial hyalinization and **atrophy** of the epithelium with **flattening** of rete pegs, the exact opposite of the elongation seen in psoriasis. **Clinical Pearls for NEET-PG:** * **Grattage Test:** Scraping the lesion increases the silvery-white scale (candle grease sign). * **Woronoff’s Ring:** A pale halo around a healing psoriatic plaque. * **Koebner’s Phenomenon:** Development of new lesions at sites of trauma (also seen in Vitiligo and Lichen Planus).

Question 38: What is the treatment of choice (TOC) in psoriatic arthropathy?

A. Methotrexate (Correct Answer)
B. 5-Fluorouracil
C. PUVA (Psoralen plus Ultraviolet A)
D. Steroids

Explanation: **Explanation:** **Methotrexate (MTX)** is considered the traditional **Treatment of Choice (TOC)** and the first-line Disease-Modifying Anti-Rheumatic Drug (DMARD) for psoriatic arthropathy. It is a folate antagonist that inhibits dihydrofolate reductase, effectively suppressing both the cutaneous hyperproliferation and the systemic inflammation responsible for joint destruction. It is particularly favored because it treats both the skin lesions and the arthritis simultaneously. **Analysis of Incorrect Options:** * **5-Fluorouracil:** This is a pyrimidine analog used primarily as a topical treatment for actinic keratosis or superficial basal cell carcinomas, and systemically for visceral malignancies. It has no role in managing psoriatic arthritis. * **PUVA:** While highly effective for extensive plaque psoriasis (skin), UV radiation cannot penetrate deep enough to treat joint inflammation. Furthermore, PUVA is now largely replaced by Narrowband UVB (NBUVB) due to safety profiles. * **Steroids:** Systemic steroids are generally **avoided** in psoriasis. While they may provide temporary joint relief, their withdrawal often triggers a severe, life-threatening rebound flare of skin symptoms, such as **Pustular Psoriasis**. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard (Modern):** While MTX is the traditional TOC, **TNF-alpha inhibitors** (e.g., Etanercept, Adalimumab) are now considered the most effective for preventing radiological progression of joint damage. * **Radiology:** Look for the "Pencil-in-cup" deformity on X-rays. * **Nail Changes:** Pitting and onycholysis are strong clinical predictors of joint involvement (Distal Interphalangeal joints). * **Drug Side Effect:** Always supplement MTX with **Folic acid** to reduce GI toxicity and bone marrow suppression.

Question 39: Berkeley membrane is seen in which condition?

A. Psoriasis (Correct Answer)
B. Pemphigus
C. Tinea capitis
D. Pityriasis rubra

Explanation: **Explanation:** **Berkeley Membrane** (also known as the **Bulkley membrane**) is a classic clinical sign of **Psoriasis**. It refers to the thin, moist, transparent layer of epidermis (the suprabasal layer) that is exposed after the silvery-white scales are completely scraped off. 1. **Why Psoriasis is correct:** In psoriasis, there is marked parakeratosis (retention of nuclei in the stratum corneum) and thinning of the suprapapillary plate. When scales are removed (Grattage test), this thin membrane is revealed. Further scraping of this membrane ruptures the dilated capillaries in the dermal papillae, leading to pinpoint bleeding, known as the **Auspitz sign**. 2. **Why other options are incorrect:** * **Pemphigus:** Characterized by intraepidermal blistering due to acantholysis. Key signs include the **Nikolsky sign** and **Asboe-Hansen sign**, not membrane exposure. * **Tinea capitis:** A fungal infection of the scalp presenting with hair loss and scaling. Diagnosis is via KOH mount or Wood’s lamp; it does not exhibit the Berkeley membrane. * **Pityriasis rubra pilaris (PRP):** While it involves hyperkeratosis, it is distinguished by "islands of sparing," follicular papules, and orange-red plaques. It is Auspitz sign negative. **Clinical Pearls for NEET-PG:** * **Grattage Test:** The process of scraping psoriasiform scales to elicit the Berkeley membrane and Auspitz sign. * **Woronoff’s Ring:** A pale halo of hypopigmentation surrounding a healing psoriatic plaque. * **Koebner Phenomenon:** Development of psoriatic lesions at sites of trauma (also seen in Vitiligo and Lichen Planus). * **Munro’s Microabscess:** Accumulation of neutrophils in the stratum corneum (histopathology).

Question 40: Munro microabscesses are seen in which of the following conditions?

A. Lichen planus
B. Mycosis fungoides
C. Psoriasis (Correct Answer)
D. Eczema

Explanation: **Explanation:** **Psoriasis** is the correct answer because **Munro microabscesses** are a pathognomonic histopathological feature of this condition. They represent collections of **neutrophils** within the **stratum corneum** (parakeratotic layer). This occurs due to the rapid migration of neutrophils from the papillary dermis through the epidermis (Kogoj’s sponges) into the horny layer, driven by chemotactic factors like IL-8 and LTB4. **Analysis of Incorrect Options:** * **Lichen Planus:** Characterized by a "saw-tooth" appearance of rete ridges, Civatte bodies (apoptotic keratinocytes), and a band-like lymphocytic infiltrate at the dermo-epidermal junction. * **Mycosis Fungoides:** A cutaneous T-cell lymphoma characterized by **Pautrier’s microabscesses**, which are clusters of atypical T-lymphocytes (not neutrophils) within the epidermis. * **Eczema:** Histologically defined by **spongiosis** (intercellular edema) and intraepidermal vesicles. While neutrophils may be present if secondarily infected, they do not form classic Munro microabscesses. **NEET-PG High-Yield Pearls:** * **Kogoj’s Macropustule:** Neutrophilic collections in the **stratum spinosum** (seen in Pustular Psoriasis). * **Auspitz Sign:** Pinpoint bleeding when psoriasis scales are removed, due to thinning of the suprapapillary plate and dilated capillaries. * **Other Histology:** Regular elongation of rete ridges ("camel foot" appearance), absent stratum granulosum, and parakeratosis. * **Key Distinction:** Remember **M**unro = **M**any Neutrophils (Psoriasis) vs. **P**autrier = **P**roliferating T-cells (Mycosis Fungoides).

Question 41: Which of the following is NOT true regarding Munro's microabscess?

A. Seen in the stratum corneum
B. Debris consists of eosinophils (Correct Answer)
C. Associated pustule may be present
D. Seen in psoriasis

Explanation: **Explanation:** The correct answer is **B (Debris consists of eosinophils)** because Munro’s microabscesses are characterized by the accumulation of **neutrophils**, not eosinophils. In the pathogenesis of Psoriasis, there is a marked chemotactic migration of neutrophils from the papillary capillaries into the epidermis. When these neutrophils aggregate within the parakeratotic layers of the **stratum corneum**, they form **Munro’s microabscesses**. If these neutrophils aggregate within the stratum spinosum (forming multilocular pustules), they are referred to as **Kogoj’s spongiform pustules**. **Analysis of other options:** * **Option A:** True. Munro’s microabscesses are specifically located in the **stratum corneum** (horny layer). * **Option C:** True. These microabscesses represent the microscopic equivalent of the clinical pustules seen in variants like pustular psoriasis. * **Option D:** True. Munro’s microabscess is a **pathognomonic** histological feature of Psoriasis. **High-Yield Clinical Pearls for NEET-PG:** * **Kogoj’s Spongiform Pustule:** Neutrophils in the stratum spinosum (seen in Psoriasis and Reiter’s syndrome). * **Psoriasis Histology Mnemonic:** "A-P-A-C-H-E" * **A**canthosis (regular) * **P**arakeratosis (nuclei in stratum corneum) * **A**bsent granular layer (Hypogranulosis) * **C**lubbing of dermal papillae * **H**orny layer microabscess (Munro’s) * **E**longated Rete ridges (Camel-foot appearance) * **Auspitz Sign:** Pinpoint bleeding on peeling a scale, due to thinning of the suprapapillary plate and dilated capillaries.

Question 42: Which of the following is NOT true about psoriatic arthritis?

A. Association with HLA-Cw6
B. Involvement of the DIP joint
C. More common in males (Correct Answer)
D. Drug of choice is methotrexate

Explanation: ### Explanation Psoriatic arthritis (PsA) is a chronic inflammatory spondyloarthropathy occurring in approximately 30% of patients with psoriasis. **Why Option C is the correct answer:** The statement that PsA is "more common in males" is **incorrect**. Unlike many other spondyloarthropathies (like Ankylosing Spondylitis), psoriatic arthritis affects **males and females equally (1:1 ratio)**. While certain subtypes may show slight predilection (e.g., the spondylitis form is slightly more common in males), the overall prevalence is gender-neutral. **Analysis of other options:** * **A. Association with HLA-Cw6:** This is the strongest genetic risk factor for Psoriasis (Type 1). While HLA-B27 is linked to the axial/spondylitis subtype of PsA, HLA-Cw6 remains the primary genetic marker for the underlying cutaneous disease. * **B. Involvement of the DIP joint:** This is a **hallmark feature** of PsA. Involvement of the Distal Interphalangeal (DIP) joints helps clinically distinguish PsA from Rheumatoid Arthritis (which typically spares the DIP joints). * **D. Drug of choice is Methotrexate:** Methotrexate is the first-line Disease-Modifying Anti-Rheumatic Drug (DMARD) for PsA, as it effectively treats both the skin lesions and the peripheral joint inflammation. **High-Yield Clinical Pearls for NEET-PG:** 1. **Moll and Wright Criteria:** The most common clinical pattern is **Asymmetric Oligoarthritis**. 2. **Arthritis Mutilans:** The most severe form, characterized by "telescoping fingers" and "pencil-in-cup" appearance on X-ray. 3. **Dactylitis:** "Sausage digits" (diffuse swelling of a finger/toe) is a highly characteristic finding. 4. **Nail Changes:** Pitting and onycholysis are strong predictors of future joint involvement.

Question 43: Which sign is observed on membrane removal of a psoriatic lesion?

A. Grottron's sign
B. Darier's sign
C. Auspitz sign (Correct Answer)
D. Crowe's sign

Explanation: **Explanation:** **Auspitz sign** is the hallmark clinical sign of Psoriasis. It refers to the appearance of **pinpoint bleeding** when the silvery-white scales (micaceous scales) are scraped off. * **Mechanism:** In psoriasis, there is significant epidermal hyperplasia (acanthosis) and thinning of the epidermis over the dermal papillae (suprapapillary thinning). Additionally, the dermal capillaries are dilated and tortuous. When the "bulk" of the scale (the **Bulkley membrane**) is removed, these fragile, superficial capillaries are ruptured, resulting in pinpoint bleeding. **Analysis of Incorrect Options:** * **A. Gottron’s sign:** Characterized by symmetric, violaceous papules over the dorsal aspect of interphalangeal joints; it is a pathognomonic feature of **Dermatomyositis**. * **B. Darier’s sign:** Refers to the formation of a wheal and flare after stroking a lesion; it is seen in **Mastocytosis** (Urticaria Pigmentosa) due to mast cell degranulation. * **D. Crowe’s sign:** Refers to axillary or inguinal freckling; it is a diagnostic criterion for **Neurofibromatosis Type 1 (NF-1)**. **High-Yield Clinical Pearls for NEET-PG:** * **Grattage Test:** The process of scraping psoriatic scales to demonstrate the "candle grease sign" (scales becoming more white/opaque) followed by the Auspitz sign. * **Koebner Phenomenon:** Appearance of new psoriatic lesions at sites of local trauma (also seen in Vitiligo and Lichen Planus). * **Woronoff Ring:** A pale halo of blanched skin surrounding a healing psoriatic plaque. * **Histopathology:** Look for Munro’s microabscesses (neutrophils in the stratum corneum) and Kogoj’s pustules (neutrophils in the stratum spinosum).

Question 44: Which of the following biologic agents approved for the treatment of psoriasis or psoriatic arthritis is not anti-TNF-alpha?

A. Etanercept
B. Alefacept (Correct Answer)
C. Infliximab
D. Adalimumab

Explanation: ### Explanation The correct answer is **Alefacept**. **1. Why Alefacept is the correct answer:** Alefacept is a recombinant fusion protein (LFA-3-IgG1) that works by a different mechanism than TNF inhibitors. It binds to **CD2** on memory-effector T cells, inhibiting their interaction with LFA-3 on antigen-presenting cells. This leads to the apoptosis of pathogenic T cells, which are central to the development of psoriasis. Note: Alefacept was the first biologic approved for psoriasis but has since been discontinued in many markets due to the emergence of more effective agents. **2. Why the other options are incorrect:** * **Etanercept:** A soluble fusion protein that acts as a decoy receptor, binding to both TNF-α and TNF-β. * **Infliximab:** A chimeric monoclonal antibody (mouse/human) that binds specifically to soluble and transmembrane TNF-α. * **Adalimumab:** A fully human monoclonal antibody directed against TNF-α. **3. High-Yield Clinical Pearls for NEET-PG:** * **TNF-α Inhibitors:** These are the "first-generation" biologics. Before starting these, always screen for **Latent Tuberculosis** (via Mantoux or IGRA) and Hepatitis B/C, as they can cause reactivation. * **IL-17 Inhibitors:** (e.g., **Secukinumab**, Ixekizumab) – Highly effective for psoriasis; watch out for worsening of Inflammatory Bowel Disease (IBD). * **IL-23 Inhibitors:** (e.g., **Guselkumab**, Risankizumab) – Target the p19 subunit. * **IL-12/23 Inhibitor:** **Ustekinumab** (targets the common p40 subunit). * **Apremilast:** An oral **PDE-4 inhibitor** used in psoriasis; common side effects include diarrhea and weight loss.

Question 45: All of the following nail changes are associated with psoriasis, EXCEPT:

A. Pitting
B. Onycholysis
C. Pterygium formation (Correct Answer)
D. Subungual hyperkeratosis

Explanation: **Explanation:** Psoriasis is a chronic inflammatory dermatosis that affects the nails in approximately 50% of patients. The correct answer is **Pterygium formation**, as this is a classic feature of **Lichen Planus**, not psoriasis. Pterygium occurs due to scarring of the nail matrix, leading to the fusion of the proximal nail fold to the nail bed. **Analysis of Options:** * **Pitting (Option A):** The most common nail finding in psoriasis. It results from focal areas of parakeratosis in the **proximal nail matrix**, which leave depressions as the nail grows out. * **Onycholysis (Option B):** This refers to the separation of the nail plate from the nail bed. In psoriasis, it often starts distally and may be surrounded by a yellowish margin (the "oil drop" or "salmon patch" sign). * **Subungual hyperkeratosis (Option D):** Caused by parakeratosis of the **nail bed**, leading to an accumulation of scales under the distal nail plate. **Clinical Pearls for NEET-PG:** * **Oil drop sign/Salmon patch:** Pathognomonic for psoriasis; represents localized nail bed involvement. * **Nail Psoriasis & Arthritis:** Nail involvement is a strong predictor of **Psoriatic Arthritis**, specifically involving the Distal Interphalangeal (DIP) joints. * **Pitting Comparison:** Psoriatic pits are typically deep, large, and irregularly scattered. In contrast, Alopecia Areata presents with fine, shallow, "geometric" pits. * **Differential:** Pterygium is seen in Lichen Planus (Dorsal pterygium) and Systemic Sclerosis/Raynaud's (Ventral pterygium/Hyponychium fusion).

Question 46: What is the topical treatment for Lichen planus?

A. Topical Salicylic acid
B. UV ray
C. Systemic steroids (Correct Answer)
D. Erythromycin

Explanation: **Explanation:** Lichen Planus (LP) is a chronic inflammatory, T-cell mediated autoimmune condition affecting the skin and mucous membranes. While the question asks for "topical treatment" but marks **Systemic Steroids** as the correct answer, this reflects a common pattern in competitive exams where the most effective "first-line" or "definitive" management for generalized/severe cases is prioritized. 1. **Why Systemic Steroids are correct:** Corticosteroids are the mainstay of treatment due to their potent anti-inflammatory and immunosuppressive properties. While topical steroids (e.g., Clobetasol) are used for localized LP, **Systemic Steroids** (Oral Prednisolone) are indicated for widespread (generalized) LP, rapidly progressive disease, or severe mucosal involvement to induce remission and prevent scarring (especially in Lichen Planopilaris). 2. **Why other options are incorrect:** * **Topical Salicylic acid:** This is a keratolytic agent used in psoriasis or ichthyosis to remove scales; it does not address the underlying lymphocytic inflammation of LP. * **UV ray (Phototherapy):** While Narrowband UVB (NBUVB) or PUVA can be used for generalized LP, they are typically second-line options if steroids are contraindicated or ineffective. * **Erythromycin:** This is an antibiotic with no role in the standard management of Lichen Planus. **High-Yield Clinical Pearls for NEET-PG:** * **The 6 P’s of LP:** Planar (flat-topped), Purple (violaceous), Polygonal, Pruritic, Papules, and Plaques. * **Wickham Striae:** Fine white reticular patterns on the surface of lesions (best seen with oil). * **Koebner Phenomenon:** Development of lesions at sites of trauma (also seen in Psoriasis and Vitiligo). * **Histopathology:** Characterized by "saw-tooth" rete ridges, Civatte bodies (apoptotic keratinocytes), and a band-like lymphocytic infiltrate at the dermo-epidermal junction. * **Association:** Chronic Hepatitis C infection is frequently associated with oral Lichen Planus.

Question 47: True isomorphic phenomenon is not seen in which of the following conditions?

A. Lichen sclerosis (Correct Answer)
B. Lichen planus
C. Vitiligo
D. Psoriasis

Explanation: **Explanation:** The **Isomorphic Phenomenon (Koebner Phenomenon)** refers to the development of characteristic skin lesions of an existing dermatosis at the site of trauma (e.g., scratching, surgical scars, or pressure) on previously uninvolved skin. **Why Lichen Sclerosus is the correct answer:** While Lichen Sclerosus can sometimes show a "Pseudo-Koebner" effect (where lesions spread due to irritation), it is **not** classically associated with the **True Isomorphic Phenomenon**. True Koebnerization is a hallmark of specific inflammatory and autoimmune conditions where the trauma triggers the exact pathophysiological process of the primary disease. **Analysis of Incorrect Options:** * **Lichen Planus (B):** One of the most common conditions to exhibit the Koebner phenomenon. Linear lesions often form along scratch marks. * **Vitiligo (C):** Depigmented patches frequently appear at sites of friction or injury (e.g., elbows, knees, or waistbands), indicating disease activity. * **Psoriasis (D):** The classic example of Koebnerization. It occurs in roughly 25% of patients, typically appearing 7–14 days after injury. **High-Yield Clinical Pearls for NEET-PG:** * **True Koebner Phenomenon:** Seen in Psoriasis, Lichen Planus, and Vitiligo. * **Pseudo-Koebner Phenomenon:** Seen in infectious conditions like **Molluscum Contagiosum** and **Verruca (Warts)**, where trauma causes local inoculation/seeding of the virus. * **Reverse Koebner Phenomenon:** The disappearance of an existing lesion following trauma to the area (seen in Psoriasis). * **Wolf’s Isotopic Response:** Appearance of a new skin disease at the exact site of a previously healed, unrelated skin disease (e.g., Granuloma annulare appearing at the site of healed Herpes Zoster).

Question 48: Munro's microabscess is seen in which of the following conditions?

A. Psoriasis (Correct Answer)
B. Discoid lupus erythematosus
C. Lichen planus
D. Mycosis fungoides

Explanation: **Explanation:** **Munro’s microabscess** is a pathognomonic histopathological feature of **Psoriasis**. It consists of small collections of **neutrophils** within the **stratum corneum** (parakeratotic layer). This occurs due to the rapid epidermal turnover and the chemotactic migration of neutrophils from the papillary dermis to the superficial epidermis. * **Why Psoriasis is correct:** In Psoriasis, there is marked epidermal hyperplasia (acanthosis) and accelerated keratinocyte maturation. Along with Munro’s microabscesses, another characteristic finding is **Kogoj’s spongiform pustule**, which represents neutrophil collections in the *stratum spinosum*. * **Why other options are incorrect:** * **Discoid Lupus Erythematosus (DLE):** Characterized by vacuolar degeneration of the basal layer, basement membrane thickening, and follicular plugging. * **Lichen Planus:** Features a "saw-tooth" appearance of rete ridges, Civatte bodies (apoptotic keratinocytes), and a band-like lymphocytic infiltrate at the dermo-epidermal junction. * **Mycosis Fungoides:** A cutaneous T-cell lymphoma characterized by **Pautrier’s microabscesses**, which are collections of atypical T-lymphocytes (not neutrophils) within the epidermis. **High-Yield Clinical Pearls for NEET-PG:** * **Auspitz Sign:** Pinpoint bleeding on peeling a psoriasis scale due to thinning of the suprapapillary plate. * **Grattage Test:** Scraping the lesion increases the visibility of silvery-white scales. * **Woronoff’s Ring:** A pale halo around a healing psoriatic plaque. * **Histology Mnemonic:** "Munro is on top (Stratum Corneum), Kogoj is in the middle (Stratum Spinosum)."

Question 49: What is the only definite indication for giving systemic corticosteroids in pustular psoriasis?

A. Pustular psoriasis with pregnancy
B. Psoriasis in a patient with alcoholic cirrhosis
C. Moderate arthritis
D. Extensive lesions (Correct Answer)

Explanation: **Explanation:** The use of systemic corticosteroids in psoriasis is generally avoided because their withdrawal can trigger a life-threatening flare-up of **Von Zumbusch (Generalized Pustular Psoriasis)**. However, in cases of severe, extensive pustular psoriasis where the patient is toxic and other systemic agents (like Methotrexate or Cyclosporine) are contraindicated or failing, systemic steroids may be used as a "rescue" therapy to control inflammation rapidly. **Analysis of Options:** * **Extensive lesions (Correct):** In generalized pustular psoriasis with widespread involvement, systemic steroids are indicated to stabilize the patient and prevent complications like high-output heart failure or sepsis, despite the risk of rebound. * **Pustular psoriasis with pregnancy:** This is known as **Impetigo Herpetiformis**. The first-line treatment is typically systemic corticosteroids or Cyclosporine, but the "definite indication" in general dermatology literature for pustular psoriasis specifically emphasizes the severity/extensiveness of the disease. * **Alcoholic cirrhosis:** This is a contraindication for Methotrexate, but not a primary indication for steroids. Acitretin or Cyclosporine would be considered based on the clinical picture. * **Moderate arthritis:** Psoriatic arthritis is primarily managed with NSAIDs, DMARDs (Methotrexate, Sulfasalazine), or Biologics (TNF-alpha inhibitors). Steroids are not the standard for moderate involvement. **High-Yield Clinical Pearls for NEET-PG:** * **The "Rebound" Phenomenon:** Sudden withdrawal of oral steroids is the most common trigger for converting stable plaque psoriasis into pustular psoriasis. * **Drug of Choice (DOC):** For Generalized Pustular Psoriasis, **Acitretin** is the first-line treatment (except in pregnancy). * **Impetigo Herpetiformis:** A variant of pustular psoriasis occurring in the 3rd trimester of pregnancy; **Cyclosporine** or steroids are preferred as Acitretin is highly teratogenic. * **Auspitz Sign:** Usually negative in pustular psoriasis (positive in plaque psoriasis).

Question 50: All of the following are used in the management of Psoriasis except?

A. Secukinumab
B. Ixekizumab
C. Reslizumab (Correct Answer)
D. Guselkumab

Explanation: ### Explanation **Correct Answer: C. Reslizumab** **1. Why Reslizumab is the Correct Answer:** Reslizumab is a humanized monoclonal antibody that binds to **Interleukin-5 (IL-5)**. IL-5 is the primary cytokine responsible for the growth, activation, and survival of **eosinophils**. Therefore, Reslizumab is indicated for the add-on maintenance treatment of **severe eosinophilic asthma**, not psoriasis. Psoriasis is primarily a Th1/Th17 mediated disease, whereas IL-5 is associated with Th2-mediated eosinophilic inflammation. **2. Analysis of Incorrect Options (Used in Psoriasis):** * **Secukinumab (Option A):** A fully human monoclonal antibody that inhibits **IL-17A**. It is highly effective and FDA-approved for moderate-to-severe plaque psoriasis and psoriatic arthritis. * **Ixekizumab (Option B):** Another potent **IL-17A inhibitor**. Like Secukinumab, it is a mainstay in the biological management of recalcitrant psoriasis. * **Guselkumab (Option D):** A monoclonal antibody that targets the **p19 subunit of IL-23**. By inhibiting IL-23, it prevents the maintenance of Th17 cells, making it a first-line biological agent for chronic plaque psoriasis. **3. NEET-PG Clinical Pearls:** * **IL-17 Inhibitors:** Secukinumab, Ixekizumab, Brodalumab (targets IL-17 receptor). *Caution: Can exacerbate Inflammatory Bowel Disease (IBD).* * **IL-23 Inhibitors:** Guselkumab, Tildrakizumab, Risankizumab. * **IL-12/23 Inhibitor:** Ustekinumab (targets the p40 subunit). * **TNF-α Inhibitors:** Infliximab, Adalimumab, Etanercept. * **Apremilast:** An oral **PDE-4 inhibitor** used in psoriasis management. * **First-line systemic drug (Non-biological):** Methotrexate remains the most commonly used systemic agent for extensive psoriasis in the Indian context.

Question 51: Which of the following is false about Lichen planus?

A. Found in skin except mucosa (Correct Answer)
B. Papules are purple colored
C. Involves basal layer of the skin
D. Shows hyperkeratosis

Explanation: ### Explanation **Lichen Planus (LP)** is a chronic inflammatory condition characterized by the "6 Ps": **P**lanar (flat-topped), **P**urple, **P**olygonal, **P**ruritic, **P**apules, and **P**laques. **Why Option A is False (The Correct Answer):** Lichen planus **frequently involves the mucosa**. In fact, oral involvement occurs in approximately 50–70% of cases and may occur in isolation without skin lesions. The most common site is the buccal mucosa, often presenting as **Wickham striae** (a white, reticulate/lace-like pattern). It can also affect the genital mucosa, nails, and scalp. **Analysis of Other Options:** * **Option B (Purple colored):** This is a classic clinical feature. The violaceous (purple) hue is due to the dense inflammatory infiltrate and the way light scatters through the thickened epidermis. * **Option C (Involves basal layer):** Histopathologically, LP is characterized by an **interface dermatitis**. There is "liquefactive degeneration" or vacuolar alteration of the **basal cell layer** caused by a T-cell mediated autoimmune attack. * **Option D (Shows hyperkeratosis):** LP typically shows **orthokeratotic hyperkeratosis** (thickening of the stratum corneum without retained nuclei), along with a prominent granular layer (hypergranulosis) and "saw-tooth" rete ridges. **High-Yield Clinical Pearls for NEET-PG:** * **Koebner Phenomenon:** Positive (lesions appear at sites of trauma). * **Wickham Striae:** White lace-like lines on the surface of papules or mucosa. * **Civatte Bodies:** Shrunken, eosinophilic, apoptotic keratinocytes found at the dermo-epidermal junction. * **Nail Findings:** Pterygium formation (v-shaped scarring of the proximal nail fold) is highly characteristic. * **Associations:** Strongly associated with **Hepatitis C virus** infection.

Question 52: Koebner's phenomenon is seen in all of the following conditions, EXCEPT?

A. Lichen planus
B. Ichthyosis (Correct Answer)
C. Psoriasis
D. Pemphigus

Explanation: **Explanation:** **Koebner’s Phenomenon** (also known as the isomorphic response) refers to the development of skin lesions in previously unaffected skin following trauma or irritation. This is a classic diagnostic sign in several inflammatory and infectious dermatoses. **Why Ichthyosis is the correct answer:** Ichthyosis is a genetic disorder of keratinization characterized by dry, scaly skin. It is **not** associated with Koebner’s phenomenon. While the skin is fragile, trauma does not trigger the specific morphology of the disease in new areas. **Analysis of Incorrect Options:** * **Psoriasis:** This is the most classic example of Koebner’s phenomenon. Trauma (like a scratch or surgical scar) triggers the hyperproliferation of keratinocytes, leading to new psoriatic plaques. * **Lichen Planus:** Along with psoriasis, this is a "true" Koebner-positive condition. Linear lesions often form along scratch marks (linear lichen planus). * **Pemphigus:** Specifically, **Pemphigus Erythematosus** (Senear-Usher syndrome) can exhibit Koebner’s phenomenon. While less common than in psoriasis, it is a documented feature in certain autoimmune bullous diseases. **High-Yield Clinical Pearls for NEET-PG:** 1. **True Koebner’s:** Psoriasis, Lichen Planus, Vitiligo. 2. **Pseudo-Koebner’s:** Seen in infectious conditions where trauma inoculates the virus into a new site (e.g., **Molluscum Contagiosum, Verruca plana**). 3. **Reverse Koebner’s:** The disappearance of an existing lesion following trauma to the site. 4. **Wolf’s Isotopic Response:** The appearance of a new skin disease at the exact site of a previously healed, unrelated skin disease (most commonly post-Herpes Zoster).

Question 53: Kogoj's pustules are seen in which condition?

A. Lichen planus
B. Pemphigus vulgaris
C. Mycosis fungoides
D. Psoriasis vulgaris (Correct Answer)

Explanation: **Explanation:** **Kogoj’s spongiform pustules** are a hallmark histopathological feature of **Psoriasis**. They are formed by the migration of neutrophils from the papillary dermis into the upper layers of the epidermis (stratum spinosum). These neutrophils aggregate between degenerating keratinocytes, creating a "spongelike" appearance. When these neutrophils migrate further up into the stratum corneum, they form **Munro’s microabscesses**. While most characteristic of pustular psoriasis, they can be seen in Psoriasis vulgaris as well. **Analysis of Incorrect Options:** * **Lichen Planus:** Characterized by "saw-tooth" rete ridges, Civatte bodies (apoptotic keratinocytes), and a band-like lymphocytic infiltrate at the dermo-epidermal junction, not neutrophilic pustules. * **Pemphigus Vulgaris:** An autoimmune blistering disease characterized by **acantholysis** (loss of intercellular connections) and the "row of tombstones" appearance on the basal layer. * **Mycosis Fungoides:** A cutaneous T-cell lymphoma characterized by **Pautrier’s microabscesses**, which are clusters of atypical T-lymphocytes (not neutrophils) within the epidermis. **NEET-PG High-Yield Pearls for Psoriasis:** * **Auspitz Sign:** Pinpoint bleeding upon removal of a psoriasis scale due to thinning of the suprapapillary plate and dilated capillaries. * **Grattage Test:** Scraping a lesion increases the visibility of silvery-white scales. * **Koebner Phenomenon:** Development of new lesions at sites of skin trauma (also seen in Lichen Planus and Vitiligo). * **Histology Mnemonic:** "Regular elongation of rete ridges" (test-tube in a rack appearance).

Question 54: What is the drug of choice for pustular psoriasis in pregnancy?

A. Methotrexate
B. Ciclosporin
C. Systemic steroids (Correct Answer)
D. Azathioprine

Explanation: **Explanation:** **Pustular psoriasis in pregnancy** (historically known as *Impetigo Herpetiformis*) is a rare but life-threatening dermatosis. It typically occurs in the third trimester and is characterized by sterile pustules on an erythematous base, often accompanied by systemic symptoms like fever, malaise, and electrolyte imbalances (hypocalcemia). **Why Systemic Steroids are the Correct Choice:** Systemic corticosteroids (e.g., Prednisolone) are the **first-line treatment** (Drug of Choice) for this condition. They are effective in rapidly controlling the acute inflammatory surge and are considered relatively safe for the fetus compared to other potent antipsoriatic agents. Prompt treatment is vital to prevent placental insufficiency and fetal distress. **Why the Other Options are Incorrect:** * **Methotrexate (A):** It is strictly **contraindicated** in pregnancy (Category X) due to its potent teratogenic effects and risk of fetal death. * **Ciclosporin (B):** While it can be used as a second-line agent in refractory cases, it is not the primary drug of choice due to risks of pregnancy-induced hypertension and low birth weight. * **Azathioprine (D):** It is generally not used for the acute management of pustular psoriasis as its onset of action is slow and it is less effective than steroids for this specific indication. **High-Yield Clinical Pearls for NEET-PG:** * **Impetigo Herpetiformis** is now considered a variant of generalized pustular psoriasis triggered by hormonal changes. * **Key Lab Abnormality:** Hypocalcemia is frequently associated and must be corrected to prevent maternal seizures. * **Retinoids (Acitretin):** The drug of choice for *non-pregnant* pustular psoriasis, but absolutely contraindicated in pregnancy (teratogenic for 3 years post-discontinuation). * **First-line for Chronic Plaque Psoriasis in pregnancy:** Narrowband UVB (NBUVB) or topical steroids.

Question 55: The oil drop sign of the nail is seen in which condition?

A. Lichen planus
B. Dermatophytes
C. Lupus vulgaris
D. Psoriasis (Correct Answer)

Explanation: **Explanation:** The **Oil drop sign** (also known as the salmon patch) is a pathognomonic clinical feature of **Psoriasis** affecting the nails. It occurs due to the accumulation of glycoprotein and inflammatory exudate in the nail bed, resulting from focal parakeratosis. This appears as a translucent, yellowish-red discoloration beneath the nail plate, resembling a drop of oil. **Analysis of Options:** * **Psoriasis (Correct):** In addition to the oil drop sign, other characteristic nail findings include **pitting** (deep, irregular, and randomly distributed), **onycholysis** (separation of the nail plate from the bed), and **subungual hyperkeratosis**. * **Lichen Planus:** Typically presents with **pterygium formation** (V-shaped scarring of the cuticle), longitudinal ridging, and thinning of the nail plate. It does not show oil drop signs. * **Dermatophytes (Onychomycosis):** Characterized by subungual debris, yellow-white discoloration, and nail thickening. While it can mimic psoriasis, it lacks the specific salmon-patch appearance. * **Lupus Vulgaris:** This is a form of cutaneous tuberculosis. It typically presents with "apple-jelly nodules" on diascopy, not specific nail matrix or bed changes. **High-Yield Clinical Pearls for NEET-PG:** * **Psoriatic Pitting:** Caused by focal parakeratosis in the **proximal nail matrix**. * **Oil Drop Sign:** Caused by involvement of the **nail bed**. * **Auspitz Sign:** Pinpoint bleeding upon removal of psoriatic scales (due to dilated capillaries in dermal papillae). * **Koebner Phenomenon:** Development of lesions at sites of trauma (also seen in Lichen Planus and Vitiligo).

Question 56: Auspitz sign is seen in:

A. Psoriasis (Correct Answer)
B. Fungal infections
C. Vitiligo
D. Melasma

Explanation: **Explanation:** **Auspitz sign** is a classic clinical diagnostic feature of **Psoriasis**. It refers to the appearance of **pinpoint bleeding points** when the silvery-white scales of a psoriatic plaque are forcibly removed. **Pathophysiology:** The underlying mechanism is related to the histopathological changes in psoriasis: 1. **Thinning of the Suprapapillary Plate:** The epidermis overlying the dermal papillae becomes significantly thinned. 2. **Dilated Capillaries:** The blood vessels within the dermal papillae become elongated, tortuous, and dilated. When scales are scraped off (Grattage test), these superficial, fragile capillaries are ruptured, leading to the characteristic pinpoint bleeding. **Why other options are incorrect:** * **Fungal infections (Tinea):** Characterized by centrifugal spread with central clearing and peripheral scaling; Auspitz sign is absent. * **Vitiligo:** An autoimmune condition causing depigmentation due to loss of melanocytes; the skin surface remains smooth without scaling. * **Melasma:** A hyperpigmentation disorder (mask of pregnancy) involving increased melanin; it does not involve epidermal thickening or scaling. **High-Yield Clinical Pearls for NEET-PG:** * **Grattage Test:** The clinical procedure used to elicit the Auspitz sign. * **Candle Grease Sign:** During the Grattage test, as scales are scraped, they become more white and opaque, resembling scrapings from a wax candle. * **Woronoff’s Ring:** A pale halo of blanched skin surrounding a healing psoriatic plaque. * **Koebner’s Phenomenon:** Development of new psoriatic lesions at sites of local trauma (also seen in Lichen Planus and Vitiligo). * **Munro’s Microabscess:** Collection of neutrophils in the stratum corneum (hallmark histopathology).

Question 57: A 30-year-old male presents with silvery, scaling plaques on his elbows and knees. His mother has a history of the same condition. What is the most likely diagnosis?

A. Acne rosacea
B. Acne vulgaris
C. Pemphigus vulgaris
D. Psoriasis vulgaris (Correct Answer)

Explanation: **Explanation:** The clinical presentation of **silvery, scaling plaques** on extensor surfaces (**elbows and knees**) in a young adult with a positive family history is the classic hallmark of **Psoriasis vulgaris**. **Why Psoriasis vulgaris is correct:** Psoriasis is a chronic, T-cell-mediated inflammatory dermatosis characterized by epidermal hyperproliferation. The "silvery-white" scale (micaceous scale) results from parakeratosis (retention of nuclei in the stratum corneum). Its predilection for extensor surfaces and strong genetic association (linked to HLA-Cw6) confirms the diagnosis in this patient. **Why the other options are incorrect:** * **Acne rosacea:** Typically presents with facial flushing, telangiectasia, and papulopustules. It lacks the thick silvery scales and extensor distribution seen here. * **Acne vulgaris:** Characterized by comedones (blackheads/whiteheads), papules, and pustules, primarily on the face, back, and chest; not scaling plaques on limbs. * **Pemphigus vulgaris:** An autoimmune blistering disease characterized by fragile, intraepidermal bullae and painful oral erosions. It involves a positive Nikolsky sign, not scaling plaques. **NEET-PG High-Yield Pearls:** * **Auspitz Sign:** Pinpoint bleeding occurs when scales are forcibly removed (due to thinning of the suprapapillary epidermis). * **Koebner Phenomenon:** Development of psoriatic lesions at sites of local trauma (also seen in Vitiligo and Lichen Planus). * **Histopathology:** Look for **Munro’s microabscesses** (neutrophils in the stratum corneum) and **Kogoj’s pustules** (neutrophils in the stratum spinosum). * **Guttate Psoriasis:** Often triggered by a Streptococcal sore throat.

Question 58: Peripheral 'Collarette of scales' is a characteristic feature of which dermatological condition?

A. Psoriasis rosea (Correct Answer)
B. Psoriasis versicolor
C. Lichen planus
D. Pityriasis rubra pilaris

Explanation: **Explanation:** The correct answer is **Pityriasis rosea** (Note: The option provided as "Psoriasis rosea" is a common nomenclature error in some question banks; the medical term is Pityriasis rosea). **1. Why Pityriasis Rosea is Correct:** The **"Collarette of scales"** is the pathognomonic clinical feature of Pityriasis Rosea (PR). It refers to a thin, fine rim of scales attached at the periphery with a free central edge, typically seen within the oval, salmon-colored erythematous plaques. This occurs because the scale peels outward from the center. PR often begins with a single, large **"Herald Patch"** followed by a generalized eruption in a **"Christmas Tree"** or "Fir Tree" distribution along the skin tension lines (Langer’s lines). **2. Why Other Options are Incorrect:** * **Pityriasis versicolor:** Characterized by "furfuraceous" (fine, powdery) scales that become prominent upon scratching (**Besnier’s sign** or the Stroke sign). * **Lichen planus:** Characterized by the 6 P's (Planar, Purple, Polygonal, Pruritic, Papules, and Plaques) and **Wickham striae** (whitish reticular lines), not peripheral scaling. * **Pityriasis rubra pilaris (PRP):** Known for follicular papules on an erythematous base, "islands of sparing," and orange-red palmoplantar keratoderma. **High-Yield Clinical Pearls for NEET-PG:** * **Etiology:** Associated with Human Herpesvirus 6 and 7 (**HHV-6/7**). * **Herald Patch:** The initial lesion, usually 2–10 cm, appearing days to weeks before the secondary eruption. * **Distribution:** Follows Langer’s lines on the trunk. * **Treatment:** Self-limiting (6–8 weeks); symptomatic relief with antihistamines or topical steroids. Narrowband UVB can be used in severe cases.

Question 59: Herald patch is characteristic of which condition?

A. Psoriasis
B. Pityriasis rosea (Correct Answer)
C. Lichen planus
D. Pityriasis rubra pilaris

Explanation: **Explanation:** **Pityriasis Rosea (PR)** is a self-limiting, inflammatory skin disorder characterized by the **Herald Patch**. This is the initial lesion, appearing in about 50–90% of cases. It is typically a single, oval, salmon-colored or erythematous plaque (2–10 cm) with a peripheral "collarette" of scale. Following this, a generalized eruption occurs in a "Christmas tree" distribution along the cleavage lines (Langer’s lines) of the trunk. **Analysis of Incorrect Options:** * **Psoriasis:** Characterized by well-demarcated, silvery-white micaceous scales on an erythematous base, typically on extensors. It lacks a single precursor herald patch and often shows the Auspitz sign. * **Lichen Planus:** Presents as the "6 Ps": Planar, Purple, Polygonal, Pruritic, Papules, and Plaques. It is associated with Wickham striae and Koebner phenomenon, not a herald patch. * **Pityriasis Rubra Pilaris (PRP):** Characterized by follicular papules on an erythematous base, "islands of sparing," and orange-red palmoplantar keratoderma. **High-Yield Clinical Pearls for NEET-PG:** * **Etiology:** Likely associated with Human Herpesvirus 6 and 7 (HHV-6/7). * **Collarette Scale:** The scale is attached peripherally with the free edge pointing inwards. * **Distribution:** "Christmas tree" or "Fir tree" pattern on the back. * **Treatment:** Usually self-limiting (6–8 weeks); symptomatic relief with antihistamines or topical steroids. * **Differential Diagnosis:** Secondary syphilis (always rule out if lesions involve palms/soles).

Question 60: The Auspitz sign is a characteristic clinical finding in which dermatological condition?

A. Psoriasis (Correct Answer)
B. Lichen planus
C. Pityriasis alba
D. All of the above

Explanation: **Explanation:** **Auspitz sign** is a classic clinical diagnostic feature of **Psoriasis**. It refers to the appearance of **pinpoint bleeding points** when the silvery scales of a psoriatic plaque are forcibly removed. **Pathophysiology:** The underlying mechanism is related to the histopathological changes in psoriasis: 1. **Thinning of the suprapapillary plate:** The epidermis overlying the dermal papillae is significantly thinned. 2. **Dilated and tortuous capillaries:** The blood vessels within the dermal papillae are elongated and congested. When the scale is removed (Grattage test), these fragile, superficial capillaries are ruptured, leading to the characteristic pinpoint bleeding. **Why other options are incorrect:** * **Lichen Planus:** Characterized by **Wickham striae** (whitish reticular lines) and the Koebner phenomenon, but it does not exhibit Auspitz sign as there is no significant suprapapillary thinning. * **Pityriasis Alba:** A form of low-grade eczema common in children, presenting as hypopigmented scaly patches. It lacks the vascular changes seen in psoriasis. **NEET-PG High-Yield Pearls:** * **Grattage Test:** The clinical procedure used to elicit the Auspitz sign. * **Munro’s Microabscesses:** Collections of neutrophils in the stratum corneum (hallmark of psoriasis). * **Kogoj’s Pustule:** Neutrophils in the stratum spinosum. * **Woronoff’s Ring:** A pale halo around a healing psoriatic plaque. * **Note:** Auspitz sign may be absent in inverse psoriasis, pustular psoriasis, or erythrodermic psoriasis.

Question 61: Efalizumab is used in the treatment of which of the following conditions?

A. Acne vulgaris
B. Atopic dermatitis
C. Psoriasis (Correct Answer)
D. All of the above

Explanation: **Explanation:** **Efalizumab** is a recombinant humanized monoclonal antibody specifically designed for the treatment of moderate-to-severe plaque **Psoriasis**. **Mechanism of Action:** Efalizumab binds to the **CD11a** subunit of Leukocyte Function-associated Antigen-1 (**LFA-1**). By doing so, it inhibits the adhesion of T-lymphocytes to intercellular adhesion molecule-1 (ICAM-1). This prevents T-cell activation, trafficking into the dermis, and attachment to keratinocytes, thereby interrupting the inflammatory cascade central to psoriasis pathogenesis. **Analysis of Options:** * **Psoriasis (Correct):** It was the primary indication for Efalizumab due to its T-cell mediated pathology. * **Acne Vulgaris (Incorrect):** Acne is primarily a disorder of the pilosebaceous unit involving sebum production and *C. acnes* colonization; T-cell targeted biologics are not used. * **Atopic Dermatitis (Incorrect):** While T-cells are involved, Efalizumab is not an approved or standard treatment for AD (where Dupilumab, an IL-4/IL-13 inhibitor, is preferred). **High-Yield Clinical Pearls for NEET-PG:** * **Black Box Warning:** Efalizumab was voluntarily withdrawn from the market (2009) due to its association with **Progressive Multifocal Leukoencephalopathy (PML)**, a fatal demyelinating disease caused by the **JC virus**. * **Target:** CD11a (LFA-1). * **Other Biologics in Psoriasis:** * TNF-α inhibitors: Infliximab, Etanercept, Adalimumab. * IL-12/23 inhibitor: Ustekinumab. * IL-17 inhibitors: Secukinumab, Ixekizumab. * IL-23 inhibitors: Guselkumab, Risankizumab.

Question 62: Which of the following is the most appropriate treatment for pustular psoriasis?

A. PUVA
B. Methotrexate (Correct Answer)
C. Steroids
D. Cyclophosphamide

Explanation: **Explanation:** **Pustular Psoriasis** (von Zumbusch type) is a severe, potentially life-threatening variant of psoriasis characterized by widespread sterile pustules on an erythematous base, often accompanied by systemic symptoms like fever and malaise. **Why Methotrexate is the correct answer:** Methotrexate is considered a first-line systemic therapy for generalized pustular psoriasis. It acts as a folate antagonist, inhibiting dihydrofolate reductase, which leads to decreased DNA synthesis and potent anti-inflammatory effects. It effectively controls the rapid epidermal turnover and neutrophilic infiltration characteristic of this condition. While **Oral Retinoids (Acitretin)** are often cited as the drug of choice for pustular psoriasis, among the given options, **Methotrexate** is the most appropriate and standard systemic treatment. **Why other options are incorrect:** * **PUVA (Phototherapy):** While used in plaque psoriasis, it is generally avoided in the acute phase of pustular psoriasis as it can further irritate the skin and exacerbate systemic symptoms. * **Steroids:** Systemic steroids are generally **contraindicated** in psoriasis. While they may provide rapid initial relief, their withdrawal frequently triggers a rebound flare-up or can actually precipitate a transition into generalized pustular psoriasis. * **Cyclophosphamide:** This is a potent immunosuppressant used in vasculitis or blistering diseases (like Pemphigus), but it is not a standard or first-line treatment for psoriasis due to its toxicity profile. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice (DOC):** Acitretin is the preferred systemic retinoid for pustular psoriasis. * **Kogoj’s Spongiform Pustule:** The characteristic histopathological feature of pustular psoriasis (neutrophils in the upper epidermis). * **Triggers:** Sudden withdrawal of systemic steroids is the most common trigger for a pustular flare. * **Pregnancy:** In Impetigo Herpetiformis (pustular psoriasis of pregnancy), **Cyclosporine** is often the preferred systemic treatment.

Question 63: Tildrakizumab was approved in March 2018 for which condition?

A. Psoriasis (Correct Answer)
B. HIV
C. Rheumatoid arthritis
D. Hepatitis C

Explanation: **Explanation:** **Tildrakizumab** is a high-affinity, humanized IgG1 kappa monoclonal antibody that specifically targets the **p19 subunit of Interleukin-23 (IL-23)**. In March 2018, the US FDA approved it for the treatment of moderate-to-severe **Plaque Psoriasis** in adults who are candidates for systemic therapy or phototherapy. **Why Psoriasis is correct:** The pathogenesis of psoriasis is driven by the **IL-23/IL-17 axis**. IL-23 is a key cytokine that promotes the survival and expansion of Th17 cells, which in turn produce IL-17, leading to keratinocyte proliferation and chronic inflammation. By inhibiting IL-23, Tildrakizumab effectively disrupts this inflammatory cascade. **Why other options are incorrect:** * **HIV & Hepatitis C:** These are viral infections treated with Antiretroviral Therapy (ART) and Direct-Acting Antivirals (DAAs), respectively. Monoclonal antibodies targeting interleukins are generally contraindicated or used with extreme caution in chronic infections due to immunosuppression. * **Rheumatoid Arthritis (RA):** While RA is an autoimmune condition, it is primarily managed with TNF-alpha inhibitors (e.g., Etanercept), IL-6 inhibitors (e.g., Tocilizumab), or JAK inhibitors. Tildrakizumab is not currently a standard treatment for RA. **High-Yield Clinical Pearls for NEET-PG:** * **Target:** IL-23 (p19 subunit). Other IL-23 inhibitors include **Guselkumab** and **Risankizumab**. * **Dosing:** It is notable for its infrequent dosing schedule (administered subcutaneously at week 0, week 4, and then every 12 weeks). * **IL-12/23 Inhibitor:** Do not confuse Tildrakizumab with **Ustekinumab**, which targets the **p40 subunit** shared by both IL-12 and IL-23. * **IL-17 Inhibitors:** Secukinumab and Ixekizumab (target IL-17A); Brodalumab (targets IL-17 receptor).

Question 64: Formation of multiple pinpoint bleeding spots on scratching the skin is characteristic of which condition?

A. Pemphigus vulgaris
B. Lupus erythematosus
C. Psoriasis (Correct Answer)
D. Herpangina

Explanation: **Explanation:** The correct answer is **Psoriasis**. The phenomenon described—multiple pinpoint bleeding spots upon scratching or removing a scale—is known as **Auspitz sign**. **Why it occurs:** In psoriasis, there is marked epidermal hyperplasia (acanthosis) and thinning of the epidermis over the dermal papillae (suprapapillary thinning). Additionally, the dermal capillaries become dilated and tortuous. When the silvery-white scales are scraped off, the thin suprapapillary plate is breached, leading to the rupture of these underlying dilated capillaries, which results in pinpoint bleeding. **Analysis of Incorrect Options:** * **Pemphigus vulgaris:** Characterized by intraepidermal blisters due to acantholysis. The hallmark sign is **Nikolsky’s sign** (dislodgement of intact superficial epidermis by shear force). * **Lupus erythematosus:** Chronic Cutaneous LE (Discoid LE) shows "carpet tack" or "tin tack" signs (follicular plugging), but not pinpoint bleeding. * **Herpangina:** A viral infection (Coxsackie A) presenting with painful vesicles and ulcers in the posterior pharynx, unrelated to scaling or Auspitz sign. **NEET-PG High-Yield Pearls:** * **Grattage Test:** The clinical procedure of scraping a psoriatic lesion to elicit Auspitz sign. * **Candle Grease Sign:** As the scale is scraped, it becomes white and opaque, resembling a drop of candle wax. * **Koebner Phenomenon:** Development of new psoriatic lesions at sites of skin trauma (also seen in Vitiligo and Lichen Planus). * **Woronoff’s Ring:** A pale halo of blanched skin surrounding a healing psoriatic plaque.

Question 65: Wickham's striae are characteristic of which dermatological condition?

A. Lichen planus (Correct Answer)
B. Psoriasis
C. Pityriasis rosea
D. Eczema

Explanation: **Explanation:** **Lichen Planus (Correct Answer):** Wickham’s striae are fine, whitish, lace-like patterns or reticulated lines seen on the surface of the papules and plaques in Lichen Planus. They are most visible on the buccal mucosa but can also be seen on cutaneous lesions after applying oil. Histologically, these striae correspond to **focal areas of hypergranulosis** (thickening of the granular layer) above the peaks of the saw-tooth rete ridges. **Incorrect Options:** * **Psoriasis:** Characterized by silvery-white micaceous scales and the **Auspitz sign** (pinpoint bleeding on scraping). Histology shows parakeratosis and regular elongation of rete ridges, not Wickham’s striae. * **Pityriasis Rosea:** Presents with a "Herald patch" followed by a "Christmas tree" distribution of lesions. The characteristic feature is a **collarette of scales** with the free edge pointing inwards. * **Eczema:** Primarily presents with erythema, edema, vesiculation (acute), and lichenification (chronic) due to scratching. It lacks the specific reticulate network of Lichen Planus. **NEET-PG High-Yield Pearls:** * **The 6 P’s of Lichen Planus:** Planar (flat-topped), Purple, Polygonal, Pruritic, Papules, and Plaques. * **Koebner Phenomenon:** Development of lesions along the site of trauma (also seen in Psoriasis and Vitiligo). * **Max-Joseph Spaces:** Small areas of separation between the epidermis and dermis due to basal cell degeneration. * **Civatte Bodies:** Shrunken, eosinophilic, apoptotic keratinocytes found in the lower epidermis/upper dermis.

Question 66: What is the treatment of choice for pustular psoriasis?

A. Psoralen plus ultraviolet A therapy (PUVA)
B. Systemic steroids
C. Methotrexate (Correct Answer)
D. Estrogen

Explanation: **Explanation:** **Pustular Psoriasis** is a severe, inflammatory variant of psoriasis characterized by sterile pustules on an erythematous base. The treatment of choice for generalized pustular psoriasis (Von Zumbusch type) is **Methotrexate** or **Oral Retinoids (Acitretin)**. 1. **Why Methotrexate is correct:** Methotrexate is a folate antagonist that inhibits dihydrofolate reductase, leading to decreased DNA synthesis. In psoriasis, it acts by inhibiting the rapid proliferation of keratinocytes and exerting a potent anti-inflammatory effect on neutrophils, which are the primary cells found in the "Kogoj’s spongiform pustules" seen in this condition. It is preferred for its rapid onset of action and efficacy in controlling systemic inflammation. 2. **Why other options are incorrect:** * **PUVA (Option A):** While effective for plaque psoriasis, PUVA is generally avoided in the acute phase of pustular psoriasis as it can be irritating and may worsen the systemic inflammatory state. * **Systemic Steroids (Option B):** These are generally **contraindicated** in psoriasis. While they may provide temporary relief, their withdrawal is a well-known trigger for precipitating a life-threatening flare of generalized pustular psoriasis. * **Estrogen (Option C):** Estrogen has no established role in the treatment of psoriasis. In fact, hormonal shifts (like pregnancy) are known triggers for Impetigo Herpetiformis (a form of pustular psoriasis). **High-Yield Clinical Pearls for NEET-PG:** * **Histopathology:** Look for **Kogoj’s spongiform pustules** (neutrophils in the stratum spinosum) and **Munro’s microabscesses** (neutrophils in the stratum corneum). * **Triggers:** Sudden withdrawal of systemic steroids is the most common trigger for pustular flares. * **First-line agents:** Acitretin is often considered the drug of choice, but Methotrexate and Cyclosporine are equally important first-line systemic options. * **Impetigo Herpetiformis:** This is pustular psoriasis occurring specifically during pregnancy; the treatment of choice here is **Systemic Corticosteroids** (an exception to the general rule) or Cyclosporine.

Question 67: Test tube rete pegs are a characteristic feature of:

A. Dilantin hyperplasia (Correct Answer)
B. Lichen planus
C. Oral submucous fibrosis
D. All of the above

Explanation: **Explanation:** The term **"test tube rete pegs"** refers to a specific histopathological pattern where the epithelial rete ridges become elongated, slender, and uniform in shape, resembling test tubes lined up in a rack. **1. Why Dilantin Hyperplasia is correct:** Dilantin (Phenytoin) is an anticonvulsant known to cause **gingival hyperplasia**. Histologically, this condition is characterized by significant epithelial hyperplasia with long, thin, and slender rete pegs extending deep into the underlying connective tissue. These are classically described as "test tube" or "finger-like" rete pegs. This is a result of increased fibroblast activity and collagen production induced by the drug. **2. Why other options are incorrect:** * **Lichen Planus:** Characterized by **"saw-tooth"** rete pegs due to the destruction of the basal cell layer (liquefactive degeneration) by a band-like lymphocytic infiltrate. * **Oral Submucous Fibrosis (OSMF):** Characterized by epithelial **atrophy** (thinning) and loss of rete pegs due to excessive collagen deposition and hyalinization in the subepithelial layers. * **Psoriasis (Comparison):** While Psoriasis also features elongated rete pegs, they are typically described as **"club-shaped"** or "regularly elongated" with thinning of the suprapapillary epithelium. **3. NEET-PG High-Yield Pearls:** * **Phenytoin (Dilantin):** Causes gingival enlargement in ~50% of users. Other drugs causing this include **Cyclosporine** and **Calcium Channel Blockers (Nifedipine)**. * **Auspitz Sign:** Bleeding when psoriasis scales are removed, due to thinning of the epithelium over dilated capillaries in the dermal papillae. * **Munro’s Microabscess:** Neutrophils in the stratum corneum (seen in Psoriasis). * **Kogoj’s Pustule:** Neutrophils in the stratum spinosum (seen in Psoriasis).

Question 68: Limpet-like cone-shaped lesions in psoriasis refer to which of the following conditions?

A. Rupioid psoriasis (Correct Answer)
B. Elephantine psoriasis
C. Ostraceous psoriasis
D. Inverse psoriasis

Explanation: **Explanation:** **Rupioid psoriasis** is the correct answer because it is characterized by highly inflammatory, thick, hyperkeratotic, and crusty lesions that are **cone-shaped or "limpet-like"** (resembling a mollusk shell). These lesions are typically circular, elevated, and have a dark, dirty appearance. They are often associated with severe disease or co-morbidities like HIV. **Analysis of Incorrect Options:** * **Elephantine psoriasis (B):** This refers to a chronic, stable form of psoriasis characterized by very large, thick, persistent plaques, usually on the lower limbs or trunk. It lacks the specific cone-shaped morphology of rupioid psoriasis. * **Ostraceous psoriasis (C):** These lesions are characterized by thick, exuberant scales that are concave and resemble an **oyster shell**. While similar to rupioid, the key distinction is the shape: Ostraceous is flatter and shell-like, whereas Rupioid is distinctly conical/limpet-like. * **Inverse psoriasis (D):** Also known as flexural psoriasis, this occurs in skin folds (axilla, groin). It is characterized by smooth, erythematous plaques **without scaling** due to the moist environment. **High-Yield Clinical Pearls for NEET-PG:** * **Auspitz Sign:** Pinpoint bleeding on removal of scales (due to thinning of suprapapillary plate). * **Grattage Test:** Scraping the lesion increases the visibility of silvery-white scales (candle grease sign). * **Koebner Phenomenon:** Development of psoriatic lesions at sites of trauma (also seen in Lichen Planus and Vitiligo). * **Histopathology:** Key features include **Munro’s microabscesses** (neutrophils in the stratum corneum) and **Kogoj’s pustules** (neutrophils in the stratum spinosum).

Question 69: What are the characteristic bodies found in Lichen planus?

A. Civatte bodies (Correct Answer)
B. HP bodies
C. Warthin Finkeldy bodies
D. Negri bodies

Explanation: **Explanation:** The correct answer is **Civatte bodies**. These are characteristic histopathological findings in **Lichen Planus (LP)**. **1. Why Civatte bodies are correct:** Lichen planus is a chronic inflammatory condition characterized by a T-cell mediated attack on basal keratinocytes. This leads to **liquefaction degeneration** of the basal layer. The damaged keratinocytes undergo apoptosis and shrink into eosinophilic, rounded, anucleated structures known as **Civatte bodies** (also called colloid or cytoid bodies). They are typically found in the lower epidermis or upper dermis and contain deposits of IgM. **2. Analysis of Incorrect Options:** * **HP (Henderson-Paterson) bodies:** These are large, intracytoplasmic inclusion bodies seen in **Molluscum Contagiosum**, caused by the Poxvirus. * **Warthin-Finkeldey bodies:** These are multinucleated giant cells with eosinophilic nuclear and cytoplasmic inclusions, characteristic of **Measles** (Rubeola). * **Negri bodies:** These are pathognomonic eosinophilic intracytoplasmic inclusions found in pyramidal cells of the hippocampus and Purkinje cells of the cerebellum in **Rabies**. **3. High-Yield Clinical Pearls for NEET-PG:** * **Histopathology of LP:** Remember the mnemonic **"SAW"**: **S**aw-tooth rete ridges, **A**canthosis, and **W**ickham striae (clinically). Other features include hypergranulosis and a band-like lymphocytic infiltrate at the dermo-epidermal junction. * **Clinical 6 P’s of LP:** Planar, Purple, Polygonal, Pruritic, Papules, and Plaques. * **Koebner Phenomenon:** Positive in Lichen Planus, Psoriasis, and Vitiligo. * **Max Joseph Space:** Small areas of separation between the epidermis and dermis due to extensive basal cell degeneration in LP.

Question 70: Wickham's striae are seen in which of the following conditions?

A. Lichen nitidus
B. Lichenoid eruption
C. Lichen striatus
D. Lichen planus (Correct Answer)

Explanation: **Explanation:** **Lichen Planus (LP)** is the correct answer. **Wickham’s striae** are characteristic fine, whitish, lace-like reticular patterns seen on the surface of the violaceous papules and plaques of Lichen planus. They are most prominent on the buccal mucosa but can also be seen on cutaneous lesions after applying oil. **Pathophysiology:** These striae correspond histologically to **focal areas of hypergranulosis** (thickening of the granular layer) and orthokeratosis above the peaks of the "saw-tooth" rete ridges. **Analysis of Incorrect Options:** * **Lichen nitidus:** Characterized by tiny, shiny, skin-colored, pinhead-sized papules ("flesh-colored beads"). Histology shows a "claw clutching a ball" appearance, but Wickham’s striae are absent. * **Lichenoid eruption:** These are drug-induced rashes that mimic LP but usually lack the classic Wickham’s striae and often show eosinophils on biopsy. * **Lichen striatus:** A self-limiting linear dermatosis that follows the **Lines of Blaschko**, typically in children. It does not exhibit the reticular white network of LP. **NEET-PG High-Yield Pearls for Lichen Planus:** * **The 6 P’s:** Planar (flat-topped), Purple (violaceous), Polygonal, Pruritic, Papules, and Plaques. * **Koebner Phenomenon:** New lesions appear at the site of trauma (also seen in Psoriasis and Vitiligo). * **Histology:** Saw-tooth rete ridges, Civatte bodies (apoptotic keratinocytes), and a band-like lymphocytic infiltrate at the dermo-epidermal junction. * **Max-Joseph Spaces:** Small areas of separation between the epidermis and dermis due to basal cell degeneration.

Question 71: The Bulkeley membrane is a characteristic histological finding in which of the following conditions?

A. Psoriasis (Correct Answer)
B. Pemphigus
C. Tinea
D. Pityriasis

Explanation: **Explanation:** The correct answer is **Psoriasis**. **Understanding the Bulkeley Membrane:** The Bulkeley membrane is a clinical and histological feature observed during the **Auspitz sign** maneuver. In Psoriasis, there is significant parakeratosis (retention of nuclei in the stratum corneum) and thinning of the suprapapillary epidermis. When psoriasiform scales are scraped off layer by layer (Grate test), a thin, moist, transparent film of the lower epidermis is revealed—this is the **Bulkeley membrane**. Removing this membrane exposes the dilated, tortuous capillaries in the dermal papillae, leading to pinpoint bleeding (Auspitz sign). **Analysis of Incorrect Options:** * **Pemphigus:** This is an autoimmune blistering disease characterized by **acantholysis** (loss of intercellular connections) and the "row of tombstones" appearance on histology. It does not involve the Bulkeley membrane. * **Tinea:** A fungal infection characterized by hyphae and spores in the stratum corneum. While it presents with scaling, it lacks the specific epidermal thinning and vascular changes seen in psoriasis. * **Pityriasis:** Conditions like Pityriasis Rosea show "cigarette paper" scaling and a "herald patch," but do not exhibit the Auspitz sign or the Bulkeley membrane. **NEET-PG High-Yield Pearls for Psoriasis:** * **Munro’s Microabscess:** Collection of neutrophils in the stratum corneum. * **Kogoj’s Pustule:** Neutrophils in the stratum spinosum. * **Woronoff’s Ring:** A pale halo around a healing psoriatic plaque. * **Koebner Phenomenon:** Development of lesions at sites of trauma (also seen in Vitiligo and Lichen Planus). * **Histology Triad:** Acanthosis (epidermal thickening), Parakeratosis, and absent/diminished Stratum Granulosum.

Question 72: All of the following are seen in psoriasis except?

A. Auspitz sign
B. 10% of cases are associated with arthritis
C. It is a premalignant disease (Correct Answer)
D. Worsening of disease during winter

Explanation: ### Explanation **Psoriasis** is a chronic, immune-mediated inflammatory skin disorder characterized by epidermal hyperproliferation. **Why Option C is the Correct Answer:** Psoriasis is **not a premalignant disease**. Unlike conditions such as Actinic Keratosis or Bowen’s disease, psoriasis does not inherently progress to malignancy. While chronic inflammation and certain treatments (like PUVA therapy) may slightly increase the risk of skin cancers (SCC/BCC), the disease itself is benign in nature. **Analysis of Incorrect Options:** * **A. Auspitz sign:** This is a classic diagnostic feature. When silvery scales are removed, pinpoint bleeding occurs due to the thinning of the suprapapillary epidermis and the presence of dilated, tortuous capillaries in the dermal papillae. * **B. 10% of cases are associated with arthritis:** Psoriatic arthritis (PsA) occurs in approximately **10–30%** of patients. It is typically seronegative (RF negative) and often involves the distal interphalangeal (DIP) joints. * **D. Worsening of disease during winter:** Psoriasis typically improves in summer due to beneficial UV radiation (which induces apoptosis of T-cells) and worsens in winter due to cold, dry air and lack of sunlight. **Clinical Pearls for NEET-PG:** * **Histopathology:** Look for Munro’s microabscesses (neutrophils in the stratum corneum) and Kogoj’s pustules (neutrophils in the stratum spinosum). * **Grattage Test:** Scraping the lesion increases the visibility of silvery scales (candle grease sign) before revealing the Auspitz sign. * **Koebner Phenomenon:** Development of new lesions at the site of trauma (also seen in Vitiligo and Lichen Planus). * **Woronoff’s Ring:** A pale halo around a healing psoriatic plaque.

Question 73: DITRA syndrome is associated with a mutation in which of the following?

A. IL-36 (Correct Answer)
B. IL-46
C. IL-10
D. IL-26

Explanation: **Explanation:** **DITRA Syndrome** (Deficiency of Interleukin-36 Receptor Antagonist) is a rare, life-threatening autoinflammatory disorder characterized by recurrent episodes of generalized pustular psoriasis (GPP), fever, and systemic inflammation. **1. Why IL-36 is Correct:** The syndrome is caused by a loss-of-function mutation in the **IL36RN gene**, which encodes the **IL-36 receptor antagonist (IL-36Ra)**. Under normal physiological conditions, IL-36Ra binds to the IL-36 receptor to inhibit pro-inflammatory signaling. In DITRA, the lack of this antagonist leads to uncontrolled, constitutive activation of the IL-36 pathway, resulting in massive cutaneous recruitment of neutrophils and the formation of sterile pustules. **2. Why the Other Options are Incorrect:** * **IL-46:** There is no well-characterized cytokine or clinical syndrome associated with "IL-46" in standard dermatological pathology. * **IL-10:** This is a potent anti-inflammatory cytokine. While its deficiency can lead to early-onset inflammatory bowel disease (IBD), it is not the primary driver of DITRA. * **IL-26:** This is a member of the IL-10 family involved in mucosal immunity and Th17 responses, but it is not linked to the specific genetic mutation found in DITRA. **Clinical Pearls for NEET-PG:** * **Clinical Presentation:** Sudden onset of high fever, malaise, and widespread sterile pustules on an erythematous base (Lakes of pus). * **Genetics:** Autosomal recessive inheritance. * **Targeted Therapy:** **Spesolimab** is a novel monoclonal antibody that inhibits the IL-36 receptor, specifically approved for GPP flares. * **Differential:** While DITRA is genetic, GPP can also be triggered by pregnancy (Impetigo Herpetiformis) or rapid withdrawal of systemic steroids.

Question 74: Munro's microabscesses are typically seen in which layer of the epidermis?

A. Stratum granulosum
B. Stratum corneum (Correct Answer)
C. Basal layer
D. Papillary tips

Explanation: **Explanation:** **Munro’s microabscesses** are a pathognomonic histological feature of Psoriasis. They represent focal collections of **neutrophils** that have migrated from the dermal papillae through the epidermis to reach the **Stratum corneum**. This occurs due to the chemotactic effect of leukotriene B4 and IL-8. * **Why Stratum Corneum is correct:** In Psoriasis, the epidermal turnover time is significantly shortened. Neutrophils trapped within the parakeratotic scales (nucleated cells in the horny layer) of the **stratum corneum** form these microabscesses. * **Stratum granulosum:** This layer is typically **thinned or absent** (hypogranulosis) in Psoriasis, making it an incorrect site for these abscesses. * **Basal layer:** This layer shows increased mitotic activity (hyperplasia) in Psoriasis, but it is not the site of neutrophil accumulation. * **Papillary tips:** While dilated capillaries and edema are seen here, neutrophil collections specifically at the papillary tips are characteristic of **Dermatitis Herpetiformis** (forming "Kogoj-like" patterns or papillary microabscesses), not Munro’s microabscesses. **High-Yield Clinical Pearls for NEET-PG:** 1. **Kogoj’s Pustule:** If neutrophils collect in the **Stratum spinosum** (malpighian layer), they are called **Spongeiform pustules of Kogoj** (commonly seen in Pustular Psoriasis). 2. **Histology Mnemonic (P-S-O-R):** **P**arakeratosis, **S**tratum granulosum decrease, **O**longated rete ridges (regular), **R**educed suprapapillary plate thickness. 3. **Auspitz Sign:** Pinpoint bleeding on scraping a psoriatic plaque occurs due to the rupture of dilated capillaries in the dermal papillae covered by a thin suprapapillary plate.

Question 75: Chloroquine can cause exacerbation of which of the following conditions?

A. Malaria
B. Psoriasis (Correct Answer)
C. Discoid lupus erythematosus (DLE)
D. Photosensitivity

Explanation: **Explanation:** **Chloroquine** and other antimalarials (like Hydroxychloroquine) are well-known triggers for the exacerbation of **Psoriasis**. The underlying mechanism involves the inhibition of the enzyme transglutaminase, which leads to increased epidermal proliferation and keratinocyte differentiation. Clinically, these drugs can provoke a flare-up of existing plaque psoriasis or induce a severe morphologic shift into **Erythrodermic** or **Pustular psoriasis**. **Analysis of Options:** * **A. Malaria:** Chloroquine is a primary treatment for sensitive strains of *Plasmodium vivax* and *falciparum*; it treats the condition rather than exacerbating it. * **C. Discoid Lupus Erythematosus (DLE):** Antimalarials are actually the **first-line systemic treatment** for DLE and Systemic Lupus Erythematosus (SLE) due to their anti-inflammatory and photoprotective properties. * **D. Photosensitivity:** Chloroquine is used therapeutically to manage various photodermatoses (e.g., Polymorphous Light Eruption) because it stabilizes lysosomal membranes and reduces UV-induced inflammation. **High-Yield Clinical Pearls for NEET-PG:** * **Drugs Exacerbating Psoriasis (Mnemonic: "BLANK"):** **B**eta-blockers, **L**ithium, **A**ntimalarials/ACE inhibitors, **N**SAIDs, **K**-sparing diuretics (and systemic steroids upon withdrawal). * **Chloroquine Side Effects:** The most feared side effect is **retinopathy** (bull’s eye maculopathy). * **Contraindication:** Chloroquine is contraindicated in patients with Psoriasis and Porphyria Cutanea Tarda (can cause hepatotoxicity).

Question 76: Which of the following is the least common site of involvement in psoriasis?

A. Scalp involvement
B. Nail involvement
C. CNS involvement (Correct Answer)
D. Arthritis

Explanation: **Explanation:** Psoriasis is a chronic, multisystem inflammatory disorder primarily mediated by T-cells (Th1 and Th17 pathways). While it is classically known as a skin condition, it is a systemic disease that frequently involves the joints and nails. **Why CNS involvement is the correct answer:** Psoriasis does **not** involve the Central Nervous System (CNS). The inflammatory process in psoriasis targets keratinocytes, synovial membranes, and the nail matrix. There is no established clinical or pathological evidence linking psoriasis directly to CNS lesions. While patients may have psychological comorbidities (like depression) due to the disease burden, the CNS is not a site of psoriatic involvement. **Analysis of incorrect options:** * **Scalp involvement (Option A):** This is one of the **most common** sites. It often presents as well-demarcated erythematous plaques with silvery-white scales extending beyond the hairline (Corona Psoriatica). * **Nail involvement (Option B):** Seen in approximately 50% of patients. High-yield signs include **pitting** (most common), **oil spots** (pathognomonic), subungual hyperkeratosis, and onycholysis. * **Arthritis (Option D):** Psoriatic Arthritis (PsA) occurs in about 30% of patients. It is a seronegative spondyloarthropathy often associated with HLA-B27. **NEET-PG High-Yield Pearls:** * **Auspitz Sign:** Pinpoint bleeding upon removal of scales (due to thinning of suprapapillary plate). * **Koebner Phenomenon:** Development of lesions at sites of trauma (also seen in Vitiligo and Lichen Planus). * **Histology:** Munro’s microabscesses (neutrophils in stratum corneum) and Kogoj’s pustules (stratum spinosum). * **Most common type:** Psoriasis Vulgaris (Chronic Plaque Psoriasis).

Question 77: Which of the following sites is least commonly involved in psoriasis?

A. Scalp involvement
B. Nail involvement
C. CNS involvement (Correct Answer)
D. Arthritis

Explanation: **Explanation:** Psoriasis is a chronic, systemic, immune-mediated inflammatory disorder primarily affecting the skin, nails, and joints. The correct answer is **CNS involvement** because psoriasis does not have any direct pathological manifestation within the Central Nervous System. While patients may experience psychological comorbidities (like depression), the disease process itself does not involve neural tissue. **Analysis of Options:** * **Scalp involvement (Option A):** This is one of the most common sites, affecting approximately 75–90% of patients. It often presents as well-demarcated erythematous plaques with silvery-white scales extending beyond the hairline. * **Nail involvement (Option B):** Seen in up to 50% of patients (and 80% of those with psoriatic arthritis). Characteristic findings include **pitting** (most common), oil spots, onycholysis, and subungual hyperkeratosis. * **Arthritis (Option D):** Psoriatic Arthritis (PsA) occurs in roughly 30% of patients. It is a seronegative spondyloarthropathy typically involving the distal interphalangeal (DIP) joints and the axial skeleton. **High-Yield Clinical Pearls for NEET-PG:** * **Auspitz Sign:** Pinpoint bleeding upon removal of a psoriasis scale due to thinning of the suprapapillary epidermis and dilated capillaries. * **Koebner Phenomenon:** Development of psoriatic lesions at sites of local trauma (also seen in Vitiligo and Lichen Planus). * **Histology:** Look for **Munro’s microabscesses** (neutrophils in the stratum corneum) and **Kogoj’s pustules** (neutrophils in the stratum spinosum). * **Treatment:** Topical Vitamin D analogues (Calcipotriol) and steroids are first-line; Methotrexate or Biologics (TNF-α inhibitors) are used for systemic disease.

Question 78: Which is the most malignant type of pustular psoriasis?

A. Palmo-plantar pustulosis
B. Acrodermatitis continua
C. Pustular bacterids
D. Von Zumbusch type (Correct Answer)

Explanation: **Explanation:** **Generalized Pustular Psoriasis (GPP)**, specifically the **Von Zumbusch type**, is the most severe and life-threatening form of psoriasis. Unlike chronic plaque psoriasis, it is characterized by the sudden onset of widespread sterile pustules on a background of intense erythema. **1. Why Von Zumbusch is the correct answer:** The term "malignant" in this context refers to its acute, severe, and potentially fatal clinical course. Patients present with systemic toxicity, including high-grade fever, chills, malaise, and leukocytosis. If left untreated, it can lead to life-threatening complications such as high-output cardiac failure, secondary bacterial infections (sepsis), and severe electrolyte imbalances (hypocalcemia and hypoalbuminemia). It is often triggered by the withdrawal of systemic corticosteroids. **2. Why the other options are incorrect:** * **Palmo-plantar pustulosis:** A localized form of pustular psoriasis confined to the palms and soles. While chronic and difficult to treat, it lacks systemic toxicity. * **Acrodermatitis continua (of Hallopeau):** A localized, chronic inflammatory condition affecting the distal digits and nail beds. It is destructive to the nails but not life-threatening. * **Pustular bacterids (Andrews’):** Historically described as pustular eruptions on palms/soles related to a distant focus of infection. It is a localized condition and not a variant of generalized psoriasis. **High-Yield Clinical Pearls for NEET-PG:** * **Histopathology:** Shows **Kogoj’s spongiform pustules** (neutrophils in the stratum spinosum) and **Munro’s microabscesses** (neutrophils in the stratum corneum). * **Triggers:** Most common trigger is the **withdrawal of systemic steroids**. * **Drug of Choice:** **Acitretin** is the first-line systemic treatment (except in pregnancy). Cyclosporine or Infliximab are used for rapid control. * **Laboratory finding:** Hypocalcemia is a classic association with the Von Zumbusch type.

Question 79: Ahritis mutilans is seen in which of the following conditions?

A. Osteoarthritis
B. Rheumatoid arthritis
C. Reiter's syndrome
D. Psoriatic arthropathy (Correct Answer)

Explanation: **Explanation:** **Arthritis Mutilans** is the most severe and destructive form of inflammatory arthritis, characterized by extensive bone resorption (osteolysis) leading to the collapse of joint surfaces. **1. Why Psoriatic Arthropathy is correct:** Arthritis mutilans is a classic, high-yield subtype of **Psoriatic Arthritis (PsA)**, occurring in about 5% of cases. The hallmark pathological process is "telescoping" of the fingers (Moll and Wright criteria), where the digits shorten due to bone loss. Radiologically, this presents as the **"Pencil-in-cup" deformity**, where the proximal bone is whittled down (pencil) and the distal bone surface is excavated (cup). **2. Why other options are incorrect:** * **Osteoarthritis:** A degenerative "wear and tear" disease characterized by joint space narrowing and osteophytes (Heberden’s/Bouchard’s nodes), not gross osteolysis. * **Rheumatoid Arthritis:** While RA causes joint destruction and deformities (Ulnar deviation, Swan neck), "mutilans" is specifically associated with the osteolytic pattern of PsA. (Note: Rarely, a mutilans-like variant exists in RA, but PsA is the primary association for exams). * **Reiter’s Syndrome (Reactive Arthritis):** Typically presents as an asymmetric oligoarthritis of the lower limbs and is associated with the triad of urethritis, conjunctivitis, and arthritis. **Clinical Pearls for NEET-PG:** * **Moll and Wright Classification:** PsA has 5 types: Asymmetric oligoarthritis (most common), Symmetric polyarthritis, DIP joint involvement, Spondylitis, and **Arthritis Mutilans** (most severe). * **Radiology Sign:** "Pencil-in-cup" appearance is pathognomonic for PsA. * **Clinical Sign:** "Opera glass hand" (La main en lorgnette) refers to the folding of skin over the shortened, telescoped joints. * **Nail Changes:** Pitting and onycholysis in a patient with joint pain strongly suggest Psoriatic Arthritis.

Question 80: Auspitz sign is seen in which of the following conditions?

A. Psoriasis (Correct Answer)
B. Lichen Planus
C. Alopecia Areata
D. Lichen Sclerosus

Explanation: **Explanation:** **Auspitz Sign** is a classic clinical diagnostic feature of **Psoriasis**. It refers to the appearance of pinpoint bleeding points when the silvery-white scales of a psoriatic plaque are forcibly removed. **1. Why Psoriasis is correct:** The underlying pathophysiology involves two key changes: **parakeratosis** (retention of nuclei in the stratum corneum) and **suprapapillary thinning** (thinning of the epidermis over the dermal papillae). Additionally, the dermal papillae contain dilated, tortuous capillaries. When the scale is removed (Grattage test), these superficial capillaries are ruptured, leading to the characteristic pinpoint bleeding. **2. Why other options are incorrect:** * **Lichen Planus:** Characterized by **Wickham’s striae** (whitish reticular patterns) and the 6 P’s (Planar, Purple, Polygonal, Pruritic, Papules, Plaques). It does not show Auspitz sign. * **Alopecia Areata:** An autoimmune non-scarring hair loss condition characterized by **Exclamation mark hairs**. * **Lichen Sclerosus:** Typically presents as "parchment-like" or "cigarette paper" skin, often in the anogenital region. **Clinical Pearls for NEET-PG:** * **Grattage Test:** The clinical procedure used to elicit Auspitz sign by scraping the lesion with a glass slide. * **Candle Grease Sign:** As the scale is scraped, it becomes more silvery-white, resembling a scratch on a wax candle. * **Bulkeley’s Membrane:** The thin, moist, transparent membrane seen just before the pinpoint bleeding occurs. * **False Negatives:** Auspitz sign is usually absent in **Pustular Psoriasis**, **Inverse Psoriasis**, and **Erythrodermic Psoriasis**. * **Koebner Phenomenon:** Also seen in Psoriasis (and Lichen Planus), where new lesions appear at the site of trauma.

Question 81: "Microabscess of Munro" is seen in which of the following conditions?

A. Lichen planus
B. Psoriasis (Correct Answer)
C. Pityriasis rosea
D. Tuberous sclerosis

Explanation: **Explanation:** **Munro’s Microabscesses** are a hallmark histopathological feature of **Psoriasis**. They consist of small collections of **neutrophils** within the **stratum corneum** (parakeratotic layer). This occurs due to the rapid turnover of keratinocytes and the chemotactic migration of neutrophils from the papillary dermis through the epidermis (Kogoj’s spongiform pustules) into the topmost layer. **Analysis of Options:** * **Psoriasis (Correct):** Characterized by the "Psoriasiform Triad": Regular elongation of rete ridges, Munro’s microabscesses, and thinning of the suprapapillary plate. * **Lichen Planus:** Histology shows "saw-tooth" rete ridges, basal cell degeneration (liquefaction necrosis), and **Wickham striae**, but not neutrophil collections. * **Pityriasis Rosea:** Features focal parakeratosis and "mound-like" edema in the dermis, but lacks the specific Munro’s microabscesses seen in psoriasis. * **Tuberous Sclerosis:** A neurocutaneous syndrome characterized by hamartomas (e.g., Angiofibromas, Ash-leaf spots, Shagreen patches). Histology shows collagenous proliferation, not epidermal neutrophilic abscesses. **High-Yield Clinical Pearls for NEET-PG:** * **Kogoj’s Spongiform Pustule:** Similar to Munro’s, but these are neutrophil collections in the **stratum spinosum** (seen in pustular psoriasis). * **Auspitz Sign:** Pinpoint bleeding when a psoriasis scale is removed due to thinning of the suprapapillary plate over dilated capillaries. * **Grattage Test:** Scraping a psoriatic lesion increases the visibility of silvery-white scales (candle grease sign). * **Koebner Phenomenon:** Development of new lesions at sites of trauma (also seen in Lichen Planus and Vitiligo).

Question 82: What is the appropriate treatment for an erythematous skin rash with multiple pus lakes in a pregnant woman?

A. Corticosteroids (Correct Answer)
B. Retinoids
C. Methotrexate
D. Psoralen with PUVA

Explanation: **Explanation:** The clinical presentation of an erythematous skin rash with "multiple pus lakes" is characteristic of **Impetigo Herpetiformis**, which is a variant of **Pustular Psoriasis** specifically occurring during pregnancy (usually in the third trimester). **1. Why Corticosteroids are correct:** Systemic corticosteroids (e.g., Prednisolone) are the first-line treatment for Impetigo Herpetiformis. They are used to rapidly control systemic inflammation and prevent maternal-fetal complications. Since this condition can lead to placental insufficiency, electrolyte imbalances, and even fetal demise, aggressive management with steroids is essential and considered safe during pregnancy compared to other systemic antipsoriatic agents. **2. Why other options are incorrect:** * **Retinoids (B):** These are highly **teratogenic** (Category X). Acitretin, commonly used for pustular psoriasis, is strictly contraindicated in pregnancy and requires avoidance of pregnancy for 3 years after discontinuation. * **Methotrexate (C):** This is a folate antagonist and a potent **teratogen** and abortifacient. It is contraindicated in pregnancy. * **Psoralen with PUVA (D):** Psoralens are mutagenic and can cross the placenta; therefore, PUVA is generally avoided. While UVB therapy is considered safe, PUVA is not. **Clinical Pearls for NEET-PG:** * **Impetigo Herpetiformis:** Despite the name, it is *not* caused by the herpes virus or an infection; it is a form of Pustular Psoriasis. * **Key Lab Finding:** Hypocalcemia is frequently associated and must be monitored to prevent tetany. * **Delivery:** The condition usually resolves rapidly after delivery but may recur in subsequent pregnancies. * **Cyclosporine:** This can be used as a second-line agent if steroids fail, as it is relatively safe in pregnancy.

Question 83: A 50-year-old patient presents with erythematous scaly plaques over the trunk and extremities for the last 10 years. The lesions are occasionally itchy, with a history of remission and relapse, and exacerbation during winters. What is the most likely diagnosis?

A. Lichen planus
B. Psoriasis vulgaris (Correct Answer)
C. Pityriasis rosea
D. Seborrheic dermatitis

Explanation: ### Explanation **Psoriasis vulgaris** is the most likely diagnosis based on the classic clinical presentation of chronic, well-demarcated erythematous scaly plaques. **Why Psoriasis is Correct:** * **Chronic Course:** A 10-year history of remission and relapse is characteristic of this autoimmune inflammatory condition. * **Morphology:** Erythematous plaques with silvery-white scales are the hallmark. * **Winter Exacerbation:** Psoriasis typically worsens in winter due to low humidity and reduced UV exposure (which normally inhibits T-cell activity in the skin). * **Distribution:** Involvement of the trunk and extremities (especially extensors) is typical. **Why Other Options are Incorrect:** * **Lichen Planus:** Presents with the "6 Ps" (Planar, Purple, Polygonal, Pruritic, Papules, and Plaques). It usually involves the flexor surfaces (wrists) and oral mucosa (Wickham striae), rather than showing winter exacerbation. * **Pityriasis Rosea:** An acute, self-limiting condition lasting 6–8 weeks. It starts with a "Herald patch" followed by a "Christmas tree" distribution. A 10-year history rules this out. * **Seborrheic Dermatitis:** Characterized by greasy, yellowish scales in "seborrheic areas" (scalp, nasolabial folds, chest). It lacks the thick, silvery scaling and chronic plaque formation seen here. **High-Yield Clinical Pearls for NEET-PG:** * **Auspitz Sign:** Pinpoint bleeding upon removal of scales (due to thinning of suprapapillary plate). * **Koebner Phenomenon:** Development of new lesions at sites of trauma (also seen in Lichen Planus and Vitiligo). * **Histopathology:** Look for **Munro’s microabscesses** (neutrophils in the stratum corneum) and **Kogoj’s pustules** (neutrophils in the stratum spinosum). * **Treatment:** Topical Vitamin D analogues (Calcipotriol) and Corticosteroids are first-line for localized disease.

Question 84: Which of the following is NOT a treatment option for psoriasis?

A. Retinoids
B. Methotrexate
C. Cyclosporine
D. Oral corticosteroids (Correct Answer)

Explanation: **Explanation:** In Psoriasis, **Oral Corticosteroids (Option D)** are generally contraindicated. While they provide rapid initial improvement due to their potent anti-inflammatory effects, their withdrawal—even with a slow taper—can trigger a life-threatening rebound flare-up. This often manifests as **Pustular Psoriasis (von Zumbusch type)** or **Erythrodermic Psoriasis**. Therefore, systemic steroids are reserved only for exceptional circumstances, such as persistent pregnancy-related psoriasis (Impetigo Herpetiformis) where other options are limited. **Analysis of other options:** * **Retinoids (Option A):** Oral retinoids like **Acitretin** are highly effective, especially in pustular and erythrodermic variants. They normalize keratinocyte proliferation and differentiation. * **Methotrexate (Option B):** A folate antagonist that inhibits dihydrofolate reductase. It is a gold-standard systemic therapy for extensive plaque psoriasis and psoriatic arthritis. * **Cyclosporine (Option C):** A calcineurin inhibitor that provides rapid induction of remission in severe, recalcitrant psoriasis by inhibiting T-cell activation. **High-Yield Clinical Pearls for NEET-PG:** * **First-line topical treatment:** Topical Corticosteroids + Vitamin D3 analogues (Calcipotriol). * **Drug of choice for Psoriatic Arthritis:** Methotrexate (or TNF-alpha inhibitors like Etanercept). * **Auspitz Sign:** Pinpoint bleeding on peeling a scale, characteristic of psoriasis. * **Woronoff Ring:** A pale halo around a healing psoriatic lesion. * **Guttate Psoriasis:** Often follows a Streptococcal sore throat; treated primarily with phototherapy (NBUVB).

Question 85: A child with a sore throat starts developing skin lesions as in the image below. Which of the following is the diagnosis?

A. Pustular psoriasis
B. Guttate psoriasis (Correct Answer)
C. Inverse psoriasis
D. Erythrodermic

Explanation: ***Guttate psoriasis***- It characteristically appears 2–3 weeks following an infection, most commonly **Streptococcal pharyngitis**, making this post-sore throat presentation highly suggestive.- The rash consists of generalized, small (2–10 mm), discrete, **"tear-drop"**-shaped papules or plaques with fine scale, often covering the trunk and extremities.*Pustular psoriasis*- This form is characterized by the presence of numerous sterile **pustules** on erythematous skin, which is a different morphology than the papular rash described.- Generalized pustular psoriasis (**von Zumbusch type**) is a severe systemic illness that is distinct from the typical post-streptococcal rash seen in children.*Erythrodermic*- This represents a severe form of psoriasis involving widespread erythema and scaling affecting **>90% of the body surface area**.- It is often associated with systemic symptoms (fever, instability) and is a medical emergency, inconsistent with the presentation following a simple sore throat.*Inverse psoriasis*- This variant exclusively affects **intertriginous areas** (skin folds) like the axilla, groin, or under the breasts.- The lesions are typically smooth, shiny, and often lack the significant scaling found in guttate or plaque psoriasis due to the moist environment.

Question 86: A 26-year-old male presented with erythematous plaques covered with silvery scales over the extensor surfaces of both arms. Punctate pitting was noted on examining the nails. What is the most likely diagnosis?

A. Eczema
B. Pityriasis rosea
C. Lichen planus
D. Psoriasis (Correct Answer)

Explanation: ***Psoriasis*** - The clinical presentation of **well-demarcated, erythematous plaques** covered with **silvery scales** on **extensor surfaces** is the hallmark of plaque psoriasis. - **Nail pitting**, as shown in the image, along with other nail changes like **onycholysis** (separation of the nail from the nail bed) and the **oil drop sign**, are highly characteristic findings in psoriasis. *Lichen planus* - Lichen planus is characterized by the "6 P's": **Pruritic, Purple, Polygonal, Planar Papules, and Plaques**, which differ significantly from the silvery-scaled lesions of psoriasis. - It commonly appears on **flexor surfaces**, such as the wrists, and is often associated with **Wickham's striae** (fine white lines on the lesions or oral mucosa). *Eczema* - Eczema (atopic dermatitis) typically presents with **poorly-demarcated, erythematous patches** with intense **pruritus**, leading to **lichenification** and **excoriations**, rather than well-defined plaques with silvery scales. - In adults, eczema classically involves the **flexor surfaces**, such as the antecubital and popliteal fossae, contrasting with the extensor distribution seen in this case. *Pityriasis rosea* - Pityriasis rosea typically begins with a solitary, larger lesion known as a **herald patch**, which is absent in this presentation. - This is followed by a generalized eruption of smaller, oval, pink papules with fine scale in a **"Christmas tree" distribution** on the trunk, which is inconsistent with the described findings.

Question 87: A patient presents with oral mucosal lesions. Identify the condition shown in the image:

A. Lichen planus (Correct Answer)
B. Dermatomyositis
C. Psoriasis
D. Dermatitis herpetiformis

Explanation: - ***Lichen planus*** - The image exhibits **Wickham's striae**, which are characteristic fine, white, lacy patterns seen on the surface of papules and plaques in lichen planus, especially on mucosal surfaces. - Lichen planus often presents as **pruritic, purple, polygonal papules**, and this appearance is consistent with its oral manifestation. - *Dermatomyositis* - Dermatomyositis is characterized by **Gottron's papules** (violaceous papules over bony prominences, especially knuckles) and a **heliotrope rash** on the eyelids. - The lesion in the image does not show these typical features of dermatomyositis. - *Psoriasis* - Psoriasis typically presents as **erythematous plaques with silvery scales**, often on extensor surfaces, and can show pinpoint bleeding (Auspitz sign) when scales are removed. - The lacy, reticular white pattern (Wickham's striae) seen in the image is not a feature of psoriasis. - *Dermatitis herpetiformis* - Dermatitis herpetiformis is characterized by intensely **pruritic vesicles and bullae** symmetrically distributed, often on extensor surfaces, associated with celiac disease. - The lesion in the image is not vesicular or bullous, nor does it present with the characteristic distribution of dermatitis herpetiformis.

Question 88: A 26-year-old male presents with greasy papules on face and chest that feel like sandpaper. Palms and soles have minute pits. Skin biopsy was performed. What is the diagnosis?

A. Hailey Hailey disease
B. Epidermolysis bullosa
C. Darier's disease (Correct Answer)
D. Incontinentia pigmenti

Explanation: ***Darier's disease*** - The presentation of **greasy papules** on the face and chest resembling "sandpaper," along with **minute pits on palms and soles**, is classic for Darier's disease. - Histologically, Darier's disease is characterized by **dyskeratosis** (premature keratinization of individual keratinocytes) and **acantholysis** (loss of cohesion between keratinocytes), which would be seen on a skin biopsy. *Hailey-Hailey disease* - This condition typically presents with **flaccid vesicles and bullae** in intertriginous areas (e.g., axillae, groin) that rupture to form erosions. - Histology shows **acantholysis** (loss of cell adhesion) creating a "dilapidated brick wall" appearance, but without the prominent dyskeratosis seen in Darier's. *Epidermolysis bullosa* - This is a group of genetic disorders characterized by **extreme skin fragility** and the formation of **blisters** (bullae) in response to minimal trauma. - The clinical presentation with greasy papules and pits is not consistent with the primary blistering nature of epidermolysis bullosa. *Incontinentia pigmenti* - This X-linked dominant disorder primarily affects females and presents with **skin lesions in distinct stages** (vesicular, verrucous, hyperpigmented, atrophic) following Blaschko's lines. - It does not typically involve greasy papules or palmoplantar pitting in the manner described.

Question 89: A 21-year-old college student presents with this clinical finding. All are true about the condition except:

A. Three genome copies per coccal unit (Correct Answer)
B. In case of absence of laboratory facility, initial treatment regimens must incorporate azithromycin or doxycycline
C. Most common complication is prostatitis
D. Nucleic acid amplification is used with >90% sensitivity

Explanation: ***Three genome copies per coccal unit*** - The image depicts **urethral discharge**, characteristic of **gonococcal or chlamydial urethritis**. - *Neisseria gonorrhoeae* is a **Gram-negative diplococcus** that contains a **single bacterial genome** per cell, not "three genome copies per coccal unit." - This statement is **false**, making it the correct answer to this "EXCEPT" question. *In case of absence of laboratory facility, initial treatment regimens must incorporate azithromycin or doxycycline* - This statement is **true**. Empirical treatment for suspected urethritis includes **azithromycin (1g single dose)** or **doxycycline (100mg BD for 7 days)** to provide coverage for both *N. gonorrhoeae* and *Chlamydia trachomatis*. - Dual therapy with **ceftriaxone plus azithromycin** is recommended when gonococcal infection is suspected. *Most common complication is prostatitis* - This statement is **true**. In untreated or inadequately treated male urethritis, complications include **prostatitis, epididymitis, and epididymo-orchitis**. - In females, complications include **pelvic inflammatory disease (PID)**, which can lead to infertility and ectopic pregnancy. *Nucleic acid amplification is used with >90% sensitivity* - This statement is **true**. **Nucleic acid amplification tests (NAATs)** are the gold standard for diagnosing both gonorrhea and chlamydia. - NAATs demonstrate **sensitivity >90-95%** and high specificity, and can be performed on first-void urine, urethral swabs, or vaginal swabs.

Question 90: All are correct about the condition shown except:

A. Parakeratosis
B. Pustular psoriasis follows streptococcal pharyngitis (Correct Answer)
C. Autosomal dominant with incomplete penetrance
D. Associated with formation of Munro micro-abscess formation

Explanation: The image shows a classic presentation of **psoriasis**, characterized by well-demarcated, erythematous plaques with silvery-white scales, typically distributed symmetrically over extensor surfaces. This question asks what is *incorrect* about psoriasis shown in the image. ***Pustular psoriasis follows streptococcal pharyngitis*** - This statement is **INCORRECT** and is the right answer to this "except" question. - It is **guttate psoriasis**, not pustular psoriasis, that characteristically follows **streptococcal pharyngitis** (especially in children and young adults). - **Pustular psoriasis** is a distinct variant characterized by sterile pustules and can be generalized (von Zumbusch type) or localized (palmoplantar), but does not have a typical association with streptococcal infection. *Parakeratosis* - **Parakeratosis** (retention of nuclei in the stratum corneum) is a **characteristic histological feature of psoriasis**. - This is seen due to rapid keratinocyte turnover and incomplete maturation. - This statement is **correct** about psoriasis. *Autosomal dominant with incomplete penetrance* - While this is a **simplified description**, psoriasis does have a **strong genetic component** with familial clustering. - The inheritance pattern is **complex and polygenic**, but some sources describe it as having autosomal dominant inheritance with **variable penetrance** (30% concordance in monozygotic twins). - Multiple genetic loci (PSORS1-9) are involved, with HLA-Cw6 being strongly associated. - This statement is **generally accepted** in medical literature, though the genetics are more complex. *Associated with formation of Munro micro-abscess formation* - **Munro micro-abscesses** are collections of neutrophils in the stratum corneum, which are a **pathognomonic histological finding in psoriasis**. - These are seen in active psoriatic lesions and represent accumulation of polymorphonuclear leukocytes. - This statement is **correct** about psoriasis.

Question 91: Choose the correct statement for the clinical sign shown in psoriasis: (Recent NEET Pattern 2016-17)

A. Punctate bleeding spots from tortuous arterioles
B. Punctate bleeding spots from elongated capillary loops (Correct Answer)
C. Punctate bleeding spots from venules
D. All are correct

Explanation: ***Punctate bleeding spots from elongated capillary loops*** - This describes **Auspitz sign**, a characteristic clinical finding in **psoriasis**, where removal of scales reveals pinpoint bleeding spots. - The bleeding occurs due to the presence of **elongated and dilated dermal capillary loops** that are close to the epidermal surface in psoriatic plaques. *Punctate bleeding spots from tortuous arterioles* - This statement is incorrect as the bleeding in Psoriasis comes specifically from the **capillary loops**, not arterioles. - Arterioles are precapillary vessels and are not typically the direct source of bleeding in Auspitz sign. *Punctate bleeding spots from venules* - This statement is incorrect. While venules are part of the microvasculature, the specific vessels responsible for Auspitz sign bleeding are the **elongated capillary loops**. - Venules are post-capillary vessels and do not typically exhibit the characteristic changes seen in psoriasis that lead to this sign. *All are correct* - This is incorrect because only the statement referring to "elongated capillary loops" accurately describes the source of punctate bleeding in the context of the Auspitz sign in psoriasis.

Question 92: A patient presents with the skin lesions shown in the image. All of the following are routinely indicated for the treatment of this condition EXCEPT:

A. Rituximab (Correct Answer)
B. Topical vitamin D
C. Cyclosporine
D. Acitretin

Explanation: ***Rituximab*** - The image displays **plaque psoriasis**, characterized by erythematous plaques with silvery scales. Rituximab, an anti-CD20 monoclonal antibody, targets B-cells and is primarily used in conditions like **lymphoma, leukemia, and rheumatoid arthritis**, not typically for psoriasis. - While some off-label uses or investigational studies might explore its role, it is **not routinely indicated** for the treatment of psoriasis. *Topical vitamin D* - **Topical vitamin D analogs** (e.g., calcipotriene, calcitriol) are a common first-line treatment for mild to moderate plaque psoriasis. They work by **inhibiting keratinocyte proliferation** and promoting their differentiation. - These agents are often used alone or in combination with topical corticosteroids to reduce inflammation and scaling. *Cyclosporine* - **Cyclosporine** is a calcineurin inhibitor used as a systemic treatment for severe psoriasis, especially in cases that are refractory to topical therapies or phototherapy. - It works by **suppressing the immune system**, thereby reducing the inflammation and rapid cell turnover seen in psoriasis. *Acitretin* - **Acitretin** is an oral retinoid indicated for severe psoriasis, particularly **pustular and erythrodermic psoriasis**, and in some cases of chronic plaque psoriasis. - It normalizes epidermal cell growth and differentiation, effective for extensive or difficult-to-treat forms of the disease.

Question 93: Which of the following layers is absent in psoriasis?

A. A
B. B (Correct Answer)
C. C
D. D

Explanation: ***B*** - The layer labeled 'B' corresponds to the **stratum granulosum (granular layer)** of the epidermis, which is **absent or markedly thinned in areas of parakeratosis** in psoriatic lesions. - The loss/absence of the stratum granulosum in psoriasis is a characteristic histological feature, particularly in regions showing parakeratosis (retention of nuclei in the stratum corneum). - This is considered the classic answer for "which layer is absent in psoriasis" in medical examinations. *A* - The layer labeled 'A' is the **stratum corneum (horny layer)**, which is actually **thickened** in psoriasis (hyperkeratosis) and shows **parakeratosis** (retention of nuclei). - The stratum corneum is not absent but rather abnormal, showing retained nuclei and increased thickness with scaling. *C* - The layer labeled 'C' represents the **stratum spinosum (prickle cell layer)**, which is significantly **thickened (acanthosis)** in psoriasis due to increased keratinocyte proliferation. - Acanthosis (thickening of the spinous layer) is a hallmark feature of psoriasis, not absence of this layer. *D* - The layer labeled 'D' points to the **stratum basale (basal layer)**, which contains actively dividing keratinocytes and is always present in the epidermis. - In psoriasis, the basal keratinocytes show increased proliferation and shortened cell cycle, leading to epidermal hyperplasia, but the layer is never absent.

Question 94: Koebner phenomenon is seen in which one of the following conditions?

A. Behçet's disease
B. Leprosy
C. Acne Vulgaris
D. Psoriasis (Correct Answer)

Explanation: ***Psoriasis*** - The **Koebner phenomenon**, or isomorphic response, is characteristic of psoriasis, where new psoriatic lesions appear on areas of **traumatized skin**. - This response is triggered by various forms of skin injury, such as scratches, surgical incisions, or sunburn. *Behçet's disease* - Behçet's disease is associated with **pathergy**, which is a hyper-reactivity to skin injury presenting as a sterile pustule or papule at the site of trauma, but it is distinct from the Koebner phenomenon. - While both involve skin reactivity to trauma, pathergy in Behçet's disease is typically a pustular response, whereas Koebner phenomenon in psoriasis results in typical psoriatic lesions. *Leprosy* - Leprosy is an infectious disease causing **skin lesions** and nerve damage, but it does not typically exhibit the Koebner phenomenon. - The skin manifestations in leprosy are primarily due to the infection with *Mycobacterium leprae* rather than an isomorphic response to trauma. *Acne Vulgaris* - Acne vulgaris is a common inflammatory skin condition involving hair follicles and sebaceous glands, characterized by **comedones, papules, pustules, and cysts**. - It is not associated with the Koebner phenomenon; new lesions arise from follicular blockage and inflammation, not from skin trauma in the same manner as psoriasis.

Question 95: A 45-year-old man presents with a 6-month history of scaly, erythematous plaques with silvery scales on his elbows, knees, and scalp. He reports occasional joint pain. His sister has similar skin problems. Examination reveals well-demarcated, erythematous plaques covered with silvery scales. Removal of scales causes pinpoint bleeding. Which of the following is most likely to be elevated in this condition?

A. IL-10
B. IL-17 (Correct Answer)
C. IL-13
D. IL-5

Explanation: ***IL-17*** - The patient's presentation with **scaly, erythematous plaques** with **silvery scales** on elbows, knees, and scalp, along with occasional joint pain, is highly suggestive of **psoriasis**. - **IL-17** is a key **pro-inflammatory cytokine** primarily produced by Th17 cells, playing a central role in the **pathogenesis of psoriasis** by promoting inflammation and keratinocyte proliferation. *IL-10* - **IL-10** is an **anti-inflammatory cytokine** that primarily functions to suppress immune responses and maintain immune tolerance. - While it can be present in some chronic inflammatory conditions, its primary role is to **downregulate inflammation**, making it unlikely to be significantly elevated as a driver of psoriasis. *IL-13* - **IL-13** is a cytokine strongly associated with **Type 2 immune responses** and allergic reactions, often seen in conditions like **asthma** and **atopic dermatitis**. - It is not a primary driver of the **Th17-mediated inflammatory processes** characteristic of psoriasis. *IL-5* - **IL-5** is primarily involved in the **growth and differentiation of eosinophils** and is a key cytokine in allergic inflammation and parasitic infections. - It does not play a significant role in the **immunopathology of psoriasis**.

Question 96: Typical silvery scales of psoriasis are absent in –

A. Groin (Correct Answer)
B. Knee
C. Elbow
D. Scalp

Explanation: ***Groin*** - Psoriasis in intertriginous areas like the **groin**, axilla, and skin folds presents as shiny, red, smooth patches without the typical silvery scales due to the moist environment. - This specific form is known as **inverse psoriasis** or flexural psoriasis. *Knee* - The knee is a common site for **plaque psoriasis**, which typically features well-demarcated, erythematous plaques covered with characteristic **silvery scales**. - Psoriasis on extensor surfaces like the knees and elbows is often dry and scaly. *Elbow* - Similar to the knee, the elbow is a classic location for **plaque psoriasis**, exhibiting the characteristic **silvery scales** over erythematous plaques. - These lesions often result from recurrent microtrauma on extensor surfaces. *Scalp* - **Scalp psoriasis** is common and manifests as thick, silvery-white scales that can extend beyond the hairline. - While it can be quite thick and adherent, the characteristic **silvery scales** are typically present.

Question 97: A patient with psoriasis was started on systemic steroids. After stopping the treatment, the patient developed universally red scaly skin with plaques losing their margins all over his body. The most likely cause is –

A. Pustular psoriasis
B. Erythrodermic psoriasis (Correct Answer)
C. Drug induced reaction
D. Bacterial infection

Explanation: ***Erythrodermic Psoriasis*** - This condition is characterized by **widespread erythema** and scaling affecting over 90% of the body surface, often with a loss of distinct plaque margins. - The sudden withdrawal of **systemic corticosteroids** in patients with psoriasis is a well-known trigger for erythrodermic psoriasis. *Pustular psoriasis* - This form presents with widespread or localized pustules, often on an erythrematous base, and may be accompanied by fever and systemic symptoms. - While it can be severe, the primary described feature here is **universal redness and scaling with plaque confluence**, not predominant pustule formation. *Drug induced reaction* - While drugs can induce or exacerbate psoriasis, the specific trigger described (withdrawal of systemic steroids) points more directly to a rebound phenomenon of the underlying psoriasis. - A drug-induced reaction would typically be an *initial* eruption or a different morphology, not a flare of pre-existing psoriasis due to *cessation* of treatment. *Bacterial infection* - A bacterial infection might cause redness, scaling, and inflammation, but it would typically be accompanied by signs of infection like fever, purulence, or pus. - The described condition is a direct rebound phenomenon after steroid withdrawal, not primarily an infective process.

Question 98: Silver plaques are a feature of:

A. Psoriasis (Correct Answer)
B. Vitiligo
C. Lichen planus
D. Albinism

Explanation: ***Psoriasis*** - **Psoriasis** is characterized by erythematous plaques covered with thick, silvery scales, typically on extensor surfaces. - These **silvery plaques** are a hallmark clinical feature due to accelerated epidermal cell turnover. *Vitiligo* - **Vitiligo** presents as **depigmented macules and patches** with well-defined borders, not silvery plaques. - It is an autoimmune condition causing the destruction of **melanocytes**, leading to loss of skin color. *Lichen planus* - **Lichen planus** typically manifests as **pruritic, polygonal, purple, planar papules and plaques** (the 6 Ps). - It does not involve silvery scales but may show **Wickham's striae**, which are fine white lines on the surface. *Albinism* - **Albinism** is a genetic condition characterized by a **lack of melanin pigment** in the skin, hair, and eyes. - This results in very fair skin, white hair, and light-colored eyes, not silvery plaques.

Question 99: All are true about psoriasis except –

A. Auspitz sign positive
B. Parakeratosis & acanthosis
C. Joint involvement in 5–10% (Correct Answer)
D. Pitting of nails
E. Koebner phenomenon

Explanation: ***Joint involvement in 5–10%*** - While **psoriasis** is a skin condition, it can involve the joints in about **30% of patients**, leading to **psoriatic arthritis**. - Therefore, stating that joint involvement occurs in only **5-10%** is incorrect, as the percentage is significantly higher. - This is the **FALSE statement** in this EXCEPT question. *Auspitz sign positive* - The **Auspitz sign** (pinpoint bleeding when scales are removed) is a classic feature of psoriasis. - It occurs due to the proximity of dilated capillaries to the thinned suprapapillary epidermis. - This is a **TRUE statement**. *Parakeratosis & acanthosis* - **Parakeratosis** (retention of nuclei in the stratum corneum) and **acanthosis** (epidermal hyperplasia) are classic histopathological features of psoriasis. - These features reflect the **rapid cell turnover** and **thickening of the epidermis** characteristic of psoriatic plaques. - This is a **TRUE statement**. *Pitting of nails* - **Nail pitting** is a common manifestation of psoriasis, affecting up to **50% of patients** with chronic plaque psoriasis and **80% of patients with psoriatic arthritis**. - Other nail changes include **onycholysis**, **subungual hyperkeratosis**, and discoloration. - This is a **TRUE statement**. *Koebner phenomenon* - **Koebner phenomenon** (isomorphic response) is the development of psoriatic lesions at sites of trauma or injury. - This is seen in approximately **25% of patients** with psoriasis and is a well-recognized clinical feature. - This is a **TRUE statement**.

Question 100: What is the most common type of psoriasis?

A. Guttate psoriasis
B. Inverse psoriasis
C. Psoriasis vulgaris (Correct Answer)
D. Pustular psoriasis

Explanation: ***Psoriasis vulgaris*** - Also known as **plaque psoriasis**, this is the most prevalent form, accounting for approximately 80-90% of all psoriasis cases. - It characteristically presents with well-demarcated, erythematous plaques covered by **silvery scales**, commonly on the extensor surfaces. *Guttate psoriasis* - This form is characterized by **small, drop-like lesions** that appear suddenly on the trunk and proximal extremities. - It often follows a **streptococcal infection** and is much less common than plaque psoriasis. *Inverse psoriasis* - This variant affects **skin folds** such as axillae, groin, and inframammary areas, presenting as smooth, red, inflamed patches. - Unlike typical psoriasis, it usually **lacks scaling** due to the moist environment and represents a less common form. *Pustular psoriasis* - Characterized by the presence of **sterile pustules** on erythematous skin, this is a less common and often more severe form of psoriasis. - It can be localized or generalized and may be triggered by certain medications or infections.

Question 101: Dithranol ointment is used for:

A. Pityriasis
B. Psoriasis (Correct Answer)
C. Pyoderma
D. Herpes zoster

Explanation: ***Psoriasis*** - Diathronol is a synonym for **dithranol**, a topical medication primarily used to treat **chronic plaque psoriasis**. - It works by inhibiting cell proliferation and normalization of keratinization, reducing the characteristic scaling and inflammation of psoriasis. *Pityriasis* - This is a general term for various skin conditions presenting with fine scales; while some forms may be treated with different topical agents, **dithranol is not a first-line treatment** for most pityriasis types. - Pityriasis Versicolor, for example, is caused by fungus and treated with antifungals. *Pyoderma* - Pyoderma refers to **bacterial skin infections** characterized by pus, such as impetigo or ecthyma. - Treatments for pyoderma typically involve **antibiotics**, either topical or systemic, and not dithranol. *Herpes zoster* - Herpes zoster, or **shingles**, is a **viral infection** caused by the varicella-zoster virus. - Treatment involves **antiviral medications** (e.g., acyclovir, valacyclovir) and sometimes pain management, not dithranol.

Question 102: All are nail changes seen in cases of psoriasis except:

A. Subungual hyperkeratosis
B. Oil drop sign
C. Mees lines (Correct Answer)
D. Pitting

Explanation: ***Mees lines*** - **Mees lines** (or Aldrich-Mees lines) are **transverse white bands** that appear in the nail plate. - They are typically associated with **heavy metal poisoning** (e.g., arsenic), chemotherapy, or systemic illnesses, not psoriasis. *Subungual hyperkeratosis* - This is a common finding in **psoriasis**, characterized by the **thickening of the nail bed** due to excessive keratin production. - It leads to lifting of the nail plate from the nail bed. *Oil drop sign* - The **oil drop sign** (or salmon patch) is a classic psoriatic nail change, presenting as a **translucent, yellowish-red discoloration** under the nail plate. - It is due to psoriasis of the nail bed. *Pitting* - **Nail pitting** refers to the presence of **small depressions or pits** on the nail surface. - It results from defective keratinization of the nail matrix and is a characteristic sign of nail psoriasis.

Question 103: A patient with psoriasis was started on systemic steroids. After stopping the treatment, the patient developed generalized pustules all over the body. The cause is most likely to be -

A. Pustular psoriasis (Correct Answer)
B. Erythrodermic Psoriasis
C. Bacterial infection
D. Drug induced reaction

Explanation: ***Pustular psoriasis*** - **Generalized pustules** developing after the abrupt cessation of systemic steroids in a patient with a history of psoriasis is highly indicative of **pustular psoriasis**. - This form of psoriasis is characterized by the sudden appearance of widespread, sterile pustules on an erythematous base and can be triggered by various factors, including **steroid withdrawal**. *Erythrodermic Psoriasis* - This form presents as widespread **redness and scaling** affecting more than 90% of the body surface. - While it can be severe and may be triggered by systemic steroid withdrawal, it does not typically manifest with **generalized pustules** as the primary feature. *Bacterial infection* - A bacterial infection might cause pustules, but they are usually associated with signs of infection such as **fever, pain, and localized inflammation**, and the pustules would likely be non-sterile and rupture. - The context of a pre-existing psoriasis diagnosis and **steroid withdrawal** points away from a primary bacterial etiology for such widespread, generalized pustules. *Drug induced reaction* - While drug reactions can cause skin eruptions, the specific presentation of **generalized pustules** in a known psoriasis patient, directly following **steroid withdrawal**, strongly suggests a flare of their underlying condition. - **Drug-induced reactions** typically have a broader range of presentations and would not be as specifically linked to pustular morphology in this context.

Question 104: All are true about psoriasis except:

A. Parakeratosis & acanthosis
B. Pitting of nails
C. Very pruritic (Correct Answer)
D. Joint involvement in 5–30%

Explanation: ***Very pruritic*** - While psoriasis can be itchy, it is generally not characterized as "very pruritic" compared to other dermatological conditions like **eczema** or **scabies**. - **Pruritus** in psoriasis tends to be mild to moderate, and it is not a defining characteristic that differentiates it from other skin disorders. *Parakeratosis & acanthosis* - **Parakeratosis** (retention of nuclei in the stratum corneum) and **acanthosis** (epidermal hyperplasia) are classic histopathological hallmarks of psoriasis. - These features reflect the rapid epidermal turnover characteristic of the condition. *Pitting of nails* - **Nail pitting**, onycholysis, and subungual hyperkeratosis are common and characteristic manifestations of psoriasis, affecting up to 50% of patients. - These nail changes are highly indicative of **psoriatic involvement**. *Joint involvement in 5–10%* - **Psoriatic arthritis**, involving inflammation of the joints, affects approximately 5-30% of individuals with psoriasis. - This statistic makes joint involvement a significant comorbidity of psoriasis.

Question 105: Which statement about systemic steroids in psoriasis is correct:

A. No definitive indication exists (Correct Answer)
B. Only as bridge therapy in rare cases
C. Emergency situations under specialist supervision only
D. Systemic steroids are contraindicated in all forms of psoriasis

Explanation: ***No definitive indication exists*** - Systemic steroids have **no established therapeutic role** in psoriasis management and are **strongly avoided** in clinical practice. - They can cause severe **rebound flares** upon withdrawal and may precipitate life-threatening **pustular psoriasis** or **erythrodermic psoriasis**. - While not absolutely contraindicated in every conceivable scenario, they provide **no long-term benefit** and actively worsen disease control by masking symptoms and creating dependency. - This statement most accurately reflects the medical consensus: systemic steroids lack definitive indications and should be avoided. *Systemic steroids are contraindicated in all forms of psoriasis* - While systemic steroids are strongly discouraged, the absolute term "contraindicated in **all forms**" is **too extreme**. - There may be rare emergency situations where short-term use under specialist care is considered when safer alternatives are unavailable. - The statement overstates the position; "no definitive indication" is more medically accurate. *Only as bridge therapy in rare cases* - Bridge therapy with systemic steroids is **not recommended** in psoriasis due to high risk of disease exacerbation. - Unlike other inflammatory conditions, psoriasis responds poorly to steroid withdrawal, making bridge therapy particularly dangerous. *Emergency situations under specialist supervision only* - This suggests systemic steroids have a defined role in emergencies, which is **misleading**. - Even in urgent situations, alternative treatments like **cyclosporine**, **methotrexate**, or **biologics** are strongly preferred. - The rare exceptions don't constitute a "definitive indication."

Question 106: Which of the following is true about Pityriasis rubra pilaris?

A. Oral cyclosporine is the drug of choice
B. Isolated patches of normal skin are found (Correct Answer)
C. Common in females
D. Occurs mainly in adults

Explanation: ***Isolated patches of normal skin are found*** - This characteristic, known as **"islands of sparing"** or **"skip areas"**, is a hallmark clinical feature of Pityriasis rubra pilaris (PRP), where small patches of unaffected skin are seen within widespread erythematous and scaling plaques. - These spared areas help differentiate PRP from other generalized erythematous skin conditions. *Oral cyclosporine is the drug of choice* - While systemic retinoids (e.g., **acitretin**) are often considered first-line systemic therapy for Pityriasis rubra pilaris, cyclosporine is a second-line option for severe, refractory cases. - **Corticosteroids** and **methotrexate** are also used, but there is no single drug of choice; treatment is often individualized based on disease severity. *Common in females* - Pityriasis rubra pilaris does not show a significant gender predilection and affects **males and females equally**. - Its incidence is generally rare, making gender-specific prevalence less notable than in some other dermatological conditions. *Occurs mainly in adults* - Pityriasis rubra pilaris has a **bimodal age distribution**, with peaks in incidence during **childhood** (juvenile form, often localized) and in **adulthood** (classical adult form, more generalized). - Therefore, stating it occurs *mainly* in adults is inaccurate as a significant proportion of cases occur in children.

Question 107: Nail changes are found in about ______ cases of psoriasis:

A. Two thirds
B. One third
C. One half (Correct Answer)
D. All cases

Explanation: ***One half*** - Approximately **50% of patients with psoriasis** will experience nail changes, which can be a key diagnostic feature. - Nail involvement is even higher, around **80-90%**, in patients with **psoriatic arthritis**. *Two thirds* - While a significant proportion, **two-thirds (roughly 66%)** is a slight overestimate of the general prevalence of nail changes in psoriasis. - This figure might be seen in specific populations or more severe cases, but not overall. *One third* - **One-third (roughly 33%)** is an underestimation of the frequency of nail changes in psoriasis. - Nail involvement is a very common manifestation of the disease. *All cases* - It is incorrect to state that **all cases of psoriasis** have nail changes. - While common, nail involvement is not universal and can range from mild to severe, or be entirely absent.

Question 108: Bleeding spots seen on removal of scales in psoriasis is called:

A. Auspitz sign (Correct Answer)
B. Punctate hemorrhage
C. Darier sign
D. Nikolsky's sign

Explanation: ***Auspitz sign*** - This sign is characterized by the appearance of **pinpoint bleeding** after the removal of psoriatic scales due to the thinning of the epidermis covering the **dilated capillaries** in the dermal papillae. - It's a classic clinical finding in **psoriasis**, indicating active disease. *Punctuate hemorrhage* - This term is a generalized description for **small, pinpoint bleeding** spots. - While the Auspitz sign involves punctate hemorrhages, it's a more specific term for this phenomenon in the context of **psoriasis** and scale removal. *Darier sign* - This sign involves the formation of a **urticarial wheal** or a visible edema response when a skin lesion is rubbed. - It is classically associated with **urticaria pigmentosa** (cutaneous mastocytosis) and not psoriasis. *Nikolsky's sign* - This sign describes the **detachment of the epidermis** from the underlying dermis with slight lateral pressure on seemingly normal skin, leading to blister formation. - It is characteristic of conditions like **pemphigus vulgaris** and **toxic epidermal necrolysis**, not psoriasis.

Question 109: Psoriasis typically seen after β-hemolytic streptococcal infection is

A. Psoriasis vulgaris
B. Guttate psoriasis (Correct Answer)
C. Erythrodermic psoriasis
D. Pustular psoriasis

Explanation: ***Guttate psoriasis*** - This form of psoriasis is classically triggered by an antecedent **streptococcal pharyngitis** (often β-hemolytic streptococcal infection), presenting as small, **tear-drop shaped lesions** scattered over the trunk and proximal extremities. - The onset is typically **acute**, occurring a few weeks after the infection. *Psoriasis vulgaris* - This is the **most common form** of psoriasis, characterized by well-demarcated, erythematous plaques with silvery scales. - While infections can exacerbate psoriasis vulgaris, it is **not typically triggered de novo** by streptococcal infections in the same way guttate psoriasis is. *Erythrodermic psoriasis* - This is a **severe and rare form** of psoriasis where nearly the entire skin surface becomes red and scaly, often accompanied by systemic symptoms like fever and malaise. - It represents a generalized inflammatory response and is usually a **flare of existing psoriasis** rather than an initial presentation following bacterial infection. *Pustular psoriasis* - This presentation involves widespread or localized pustules, often on a red, tender skin base, and can be associated with systemic symptoms. - While infections can be a trigger, **streptococcal infections** are not the classic trigger for pustular psoriasis outbreaks as they are for guttate psoriasis.

Question 110: All of the following are used in systemic therapy of psoriasis except

A. Methotrexate
B. Cyclosporine
C. Oral glucocorticoids (Correct Answer)
D. Acitretin

Explanation: ***Oral glucocorticoids*** - **Oral glucocorticoids** are generally avoided in psoriasis because they can precipitate severe **rebound flares** upon discontinuation or during dose tapering. - While they can temporarily suppress inflammation, the risk of worsening psoriasis and other systemic side effects makes them unsuitable for long-term systemic therapy. *Methotrexate* - **Methotrexate** is a commonly used systemic agent for psoriasis due to its **immunosuppressive** and **anti-proliferative effects**, targeting rapidly dividing cells. - It works by inhibiting dihydrofolate reductase and is typically given once weekly for chronic plaque psoriasis. *Cyclosporine* - **Cyclosporine** is an effective systemic immunosuppressant used for severe, resistant psoriasis, particularly when rapid control is needed. - It primarily acts by inhibiting **T-cell activation** and proliferation, thereby reducing the inflammatory response in psoriasis. *Acitretin* - **Acitretin** is an oral retinoid derivative of vitamin A, used in severe forms of psoriasis, especially **pustular** and **erythrodermic** types. - It works by modulating **keratinocyte differentiation** and proliferation, helping to normalize skin cell growth.

Question 111: In which of the following, Koebner phenomenon is NOT seen -

A. psoriasis
B. Lichen simplex chronicus (Correct Answer)
C. Lichen planus
D. Lichen nitidus

Explanation: ***Lichen simplex chronicus*** - The **Koebner phenomenon**, which involves the appearance of skin lesions at sites of trauma, is not typically observed in **lichen simplex chronicus**. - This condition is characterized by **chronic scratching and rubbing**, leading to thickened, leathery skin, but the lesions themselves do not spread to new trauma sites in the classic Koebner fashion. *Psoriasis* - The **Koebner phenomenon** (also known as the isomorphic response) is highly characteristic of psoriasis, where new psoriatic lesions develop in areas of skin trauma. - This response is a key diagnostic feature and helps differentiate psoriasis from other skin conditions. *Lichen planus* - The **Koebner phenomenon** is a well-recognized feature of lichen planus, where the skin lesions can appear along lines of trauma, such as scratches or surgical scars. - This isomorphic response can be helpful in the diagnosis and understanding of the disease pathogenesis. *Lichen nitidus* - **Lichen nitidus** is another dermatological condition in which the **Koebner phenomenon** is observed. - New papules can erupt at sites of minor trauma, indicating an isomorphic response similar to that seen in psoriasis and lichen planus.

Question 112: Antibiotics are indicated in which type of psoriasis?

A. Chronic plaque psoriasis
B. Erythrodermic psoriasis
C. Guttate (Correct Answer)
D. Pustular

Explanation: ***Guttate*** - **Guttate psoriasis** is frequently triggered by a preceding **streptococcal infection**, such as streptococcal pharyngitis (strep throat). - Treatment with **antibiotics** (e.g., penicillin) is indicated to eradicate the streptococcal infection, which can help in resolving the psoriatic lesions and preventing future flares. *Chronic plaque psoriasis* - This is the most common form of psoriasis, characterized by **well-demarcated, erythematous plaques with silvery scales**. - Its etiology is primarily **autoimmune**, and while infections can sometimes exacerbate it, antibiotics are not a standard part of its treatment. *Erythrodermic psoriasis* - This is a severe, generalized form of psoriasis affecting nearly the **entire skin surface**, leading to significant inflammation and desquamation. - While patients with erythrodermic psoriasis are at higher risk for **secondary infections** due to skin barrier disruption, antibiotics are only indicated for treating these secondary bacterial infections, not for the psoriasis itself. *Pustular* - **Pustular psoriasis** is characterized by the presence of sterile pustules on an erythematous base. - Though severe, it is primarily an **inflammatory condition**, and antibiotics are not used in its primary management unless a secondary bacterial infection is suspected and confirmed.

Question 113: The following is an important feature of psoriasis:

A. Erythematous macules
B. Crusting
C. Silvery Scaling (Correct Answer)
D. Coarse bleeding

Explanation: ***Silvery Scaling*** - **Silvery scaling** is a hallmark clinical feature of **psoriasis**, resulting from the rapid turnover of skin cells. - These scales often appear on **erythematous plaques** and can be easily scraped off, sometimes revealing pinpoint bleeding underneath (**Auspitz sign**). *Erythematous macules* - While psoriasis does involve **erythema** (redness), the primary lesions are typically **plaques**, not macules (flat, discolored spots). - Macules are seen in other dermatological conditions such as drug eruptions or early viral exanthems, but not as the definitive feature of psoriasis. *Crusting* - **Crusting** is a feature of conditions involving exudation and drying of serum, blood, or pus, such as **impetigo** or **eczema** with secondary infection. - It is not a characteristic primary lesion of psoriasis, although secondary infection of psoriatic plaques could theoretically lead to crusting. *Coarse bleeding* - **Coarse bleeding** is not a primary feature of psoriasis; however, when psoriatic scales are removed, pinpoint bleeding known as the **Auspitz sign** can occur. - This is distinct from frank, coarse bleeding and is a diagnostic clue rather than a characteristic lesion in itself.

Question 114: Treatment of choice for Pustular psoriasis is:

A. Methotrexate (Correct Answer)
B. Psoralen - UV therapy
C. Systemic steroid
D. Estrogen

Explanation: ***Methotrexate*** - **Methotrexate** is a systemic immunosuppressant often considered the first-line treatment for severe forms of **pustular psoriasis** due to its efficacy in reducing inflammation and hyperproliferation of skin cells. - It works by inhibiting **dihydrofolate reductase**, thereby interfering with DNA synthesis and cell division, which is crucial in rapidly dividing cells like those found in psoriasis. *Psoralen - UV therapy* - **Psoralen and ultraviolet A (PUVA)** therapy can be used for chronic plaque psoriasis, but it is generally **contraindicated or used with extreme caution** in pustular psoriasis due to the risk of exacerbating the disease or causing irritation. - **UV light therapy** can sometimes trigger or worsen pustular flares, especially in acute generalized pustular psoriasis. *Systemic steroid* - While systemic steroids can provide temporary relief by addressing inflammation, their use in pustular psoriasis is generally **not recommended for long-term management** due to the high risk of severe rebound flares upon withdrawal. - Withdrawal of **systemic corticosteroids** can precipitate or worsen generalized pustular psoriasis, making them a less desirable long-term treatment option. *Estrogen* - **Estrogen** has no direct role in the treatment of psoriasis. Psoriasis is an inflammatory skin condition, and its pathophysiology is not directly influenced by estrogen levels. - Hormonal therapies are not indicated for the management of psoriasis, including its pustular forms.

Question 115: Which one of these should not be used in severe widespread psoriasis?

A. Methotrexate
B. Oral retinoids
C. Cyclosporin
D. Oral glucocorticoids (Correct Answer)

Explanation: ***Oral glucocorticoids*** - While they may provide temporary relief, **oral glucocorticoids** can exacerbate psoriasis upon withdrawal, leading to a severe flare-up or **pustular psoriasis**. - Their long-term use is associated with numerous side effects, making them unsuitable for widespread, chronic conditions like severe psoriasis. *Methotrexate* - **Methotrexate** is a systemic agent commonly used for severe psoriasis due to its immune-modulating and anti-proliferative effects. - It is effective in reducing inflammation and slowing down epidermal cell turnover. *Oral retinoids* - **Oral retinoids** like acitretin are effective systemic treatments for severe widespread psoriasis, especially **pustular** and **erythrodermic** forms. - They work by normalizing keratinocyte proliferation and differentiation. *Cyclosporin* - **Cyclosporin** is a potent immunosuppressant widely used for severe psoriasis, particularly when rapid disease control is needed. - It works by inhibiting T-cell activation and is highly effective in clearing psoriatic lesions.

Question 116: PUVA therapy is used in:

A. Melasma
B. Lichen planus
C. Psoriasis (Correct Answer)
D. Freckles

Explanation: ***Psoriasis*** - **PUVA (Psoralen plus ultraviolet A)** therapy is a well-established and effective treatment for **moderate-to-severe psoriasis**. - Psoralen is a photosensitizing agent that, when activated by UVA light, inhibits **DNA synthesis** and reduces cell proliferation in the affected skin. - PUVA is considered a **gold standard phototherapy** for psoriasis, particularly for extensive plaque psoriasis and generalized disease. *Melasma* - Melasma is a **hyperpigmentary disorder** characterized by dark patches on the face. - While some light-based therapies are used, **topical agents** like hydroquinone and chemical peels are the primary treatments, and PUVA is not typically indicated due to the risk of worsening hyperpigmentation. *Lichen planus* - Lichen planus is an **inflammatory skin condition** that can be treated with phototherapy including **PUVA**, particularly for oral lichen planus and widespread cutaneous disease. - However, **narrowband UVB** is generally preferred as first-line phototherapy due to fewer side effects. - While PUVA has a role in lichen planus, psoriasis remains the **primary and most established indication** for this therapy. *Freckles* - Freckles are **benign pigmented macules** and do not require medical treatment. - Protection from **UV exposure** and cosmetic treatments like laser therapy for aesthetic reasons are sometimes used, but PUVA is entirely inappropriate and would cause harm.

Question 117: In psoriasis, the following are seen except:

A. Skin involvement
B. CNS involvement (Correct Answer)
C. Nail changes
D. Arthritis

Explanation: ***CNS involvement*** - Psoriasis is primarily a **skin disorder** with systemic manifestations but typically does **not directly involve the central nervous system**. - While patients with psoriasis may experience symptoms like depression or anxiety, these are generally considered **comorbid conditions** rather than direct manifestations of psoriatic pathology in the CNS. *Skin involvement* - **Plaque psoriasis**, the most common form, is characterized by well-demarcated, erythematous plaques with silvery scales. - Psoriasis directly affects the skin, leading to rapid **keratinocyte proliferation** and inflammation. *Nail changes* - **Onycholysis (separation of the nail from the nail bed)**, **pitting**, and **oil spots** (yellow-brown discolorations under the nail) are common in psoriasis. - These nail changes can occur with or without concurrent skin involvement. *Arthritis* - **Psoriatic arthritis (PsA)** is a chronic inflammatory arthritis associated with psoriasis, affecting up to 30% of patients. - It can involve peripheral joints, the **axial skeleton**, and entheses, often presenting with symptoms like stiffness and pain.

Question 118: In Erythrodermic psoriasis, _____ or more of body surface area is involved

A. 90% (Correct Answer)
B. 85%
C. 95%
D. 80%

Explanation: ***90%*** - Erythrodermic psoriasis is defined by the involvement of **90% or more of the total body surface area** with erythema and scaling. - This extensive skin involvement leads to significant systemic symptoms and is considered a **medical emergency**. - It represents the most severe form of psoriasis with near-complete body involvement. *85%* - While representing extensive involvement, **85%** does not meet the diagnostic threshold for erythrodermic psoriasis. - The definition specifically requires **≥90%** body surface area involvement. *95%* - Although **95%** body surface area involvement would certainly qualify as erythrodermic psoriasis, it exceeds the minimum diagnostic threshold. - The defining cutoff is **90% or more**, not 95%. *80%* - Involvement of **80%** of the body surface area, while extensive, does not meet the criteria for erythrodermic psoriasis. - This would typically be classified as **severe plaque psoriasis** rather than erythrodermic form.

Question 119: Auspitz sign is seen in?

A. Psoriasis (Correct Answer)
B. Vitiligo
C. Contact dermatitis
D. Lichen Planus

Explanation: ***Psoriasis*** - Auspitz sign refers to the appearance of **pinpoint bleeding** after the removal of psoriatic scales. - This phenomenon is caused by the thinning of the **epidermis** over the dermal papillae, making the superficial blood vessels more prone to rupture. *Vitiligo* - Vitiligo is characterized by **patches of depigmentation** due to the destruction of melanocytes. - It does not involve scaling or bleeding upon scratching. *Contact dermatitis* - Contact dermatitis is an **inflammatory skin reaction** caused by contact with an allergen or irritant, presenting as redness, itching, and sometimes vesicles. - While scratching can cause bleeding, it does not typically produce the specific **pinpoint bleeding** pattern seen with Auspitz sign. *Lichen Planus* - Lichen planus is an **inflammatory condition** affecting the skin, hair, nails, and mucous membranes, characterized by **pruritic, polygonal, purple papules**. - It does not present with scaling that reveals pinpoint bleeding when removed.

Question 120: A 30-year-old male presented with silvery scales on elbow and knee, that bleed on removal. The probable diagnosis is:

A. Secondary syphilis
B. Psoriasis (Correct Answer)
C. Pityriasis
D. Seborrhoeic dermatitis

Explanation: ***Psoriasis*** - The presence of **silvery scales** on the elbows and knees, which **bleed upon removal** (Auspitz sign), is a classic presentation of **plaque psoriasis**. - Psoriasis is a chronic inflammatory skin condition characterized by **accelerated epidermal turnover**. *Secondary syphilis* - Secondary syphilis typically presents with a **generalized maculopapular rash**, which can affect the palms and soles, but it does not usually feature silvery scales or the Auspitz sign. - Other common symptoms of secondary syphilis include **fever, lymphadenopathy, and condyloma lata**. *Pityriasis* - **Pityriasis rosea** is characterized by an oval, fawn-colored, scaly rash, often preceded by a **herald patch**, and usually resolves spontaneously. It does not typically present with silvery scales or bleeding on removal. - **Pityriasis versicolor** is caused by yeast and presents as hypopigmented or hyperpigmented macules with fine scales, commonly on the trunk, not silvery scales on elbows and knees. *Seborrhoeic dermatitis* - Seborrhoeic dermatitis involves greasy, yellowish scales on red skin, typically affecting areas rich in sebaceous glands like the scalp, face (nasolabial folds, eyebrows), and chest. - It does not present with silvery scales or the Auspitz sign, which are specific to psoriasis.

Question 121: Most important feature of psoriasis?

A. Erythema
B. Crusting
C. Oozing
D. Scaling (Correct Answer)

Explanation: ***Scaling*** - **Scaling** is the most characteristic and prominent feature of **psoriasis**, resulting from the rapid turnover of skin cells. - The scales are typically **silvery-white** and can be thick, particularly on extensor surfaces like elbows and knees. *Erythema* - While **erythema (redness)** is present in psoriatic lesions due to inflammation and increased blood flow, it is not as specific as scaling. - Many dermatological conditions present with redness, making it less diagnostic on its own. *Crusting* - **Crusting** is generally associated with weeping lesions, infections, or dried exudates, which are not typical primary features of uncomplicated psoriasis. - It might occur secondary to scratching or infection, but isn't a hallmark lesion. *Oozing* - **Oozing** indicates active inflammation, fluid exudation, or infection, and is not a typical characteristic of classical psoriatic plaques. - Psoriasis lesions are usually dry and scaly, rather than moist or oozing.

Question 122: Psoriasis is exacerbated by -

A. Beta-blockers
B. Lithium
C. Antimalarials
D. All of the options (Correct Answer)

Explanation: ***All of the above*** - **Beta-blockers**, **lithium**, and **antimalarial drugs** are well-established medications that can exacerbate or trigger psoriasis flares. - Patients with psoriasis require careful monitoring when these medications are prescribed, with consideration of alternative treatments when feasible. ***Beta-blockers*** - **Non-selective beta-blockers** (particularly propranolol) can worsen existing psoriasis or induce new-onset disease. - The mechanism likely involves alterations in **T-cell function** and **epidermal proliferation**. - Risk is higher with non-selective agents compared to cardioselective beta-blockers. ***Lithium*** - **Lithium**, used for bipolar disorder, is a frequent and well-documented psoriasis trigger. - Can induce or worsen various forms including **plaque psoriasis**, **pustular psoriasis**, and **erythrodermic psoriasis**. - Exacerbations typically occur within weeks to months of initiation. ***Antimalarials*** - **Chloroquine** and **hydroxychloroquine** can precipitate severe psoriasis flares. - Particularly associated with **erythrodermic** and **generalized pustular psoriasis**. - Mechanism involves **immune cell activation** and amplification of inflammatory pathways.

Question 123: Koebner's phenomenon is characteristic of –

A. Psoriasis (Correct Answer)
B. Lupus vulgaris
C. Pemphigus vulgaris
D. Pityriasis rosea

Explanation: ***Psoriasis*** - **Koebner's phenomenon**, or isomorphic response, refers to the development of new lesions at sites of **skin trauma** (e.g., cuts, scratches, burns, or friction). - This phenomenon is **most characteristically associated with psoriasis** and is considered a distinctive clinical feature that helps in diagnosis. - While Koebner's phenomenon can occur in other dermatological conditions (such as lichen planus, vitiligo, and rarely pemphigus), **psoriasis remains the classic and most frequent example** in clinical practice and medical education. *Lupus vulgaris* - This is a chronic and progressive form of **cutaneous tuberculosis**, characterized by reddish-brown plaques with an "apple jelly" appearance on diascopy. - While skin trauma can sometimes trigger or worsen infections, **Koebner's phenomenon is not a characteristic feature** of lupus vulgaris. *Pemphigus vulgaris* - Pemphigus vulgaris is an **autoimmune blistering disease** affecting the skin and mucous membranes. - It is **primarily characterized** by flaccid blisters that rupture easily and a positive **Nikolsky's sign** (epidermis detaches with slight lateral pressure). - While Koebner's phenomenon has been rarely reported in pemphigus, **Nikolsky's sign is the pathognomonic feature**, not Koebner's phenomenon. *Pityriasis rosea* - This is a common, acute, self-limiting skin eruption that typically begins with a **herald patch** followed by smaller, oval, fine-scaling patches in a **'Christmas tree' pattern** on the trunk. - Its etiology is thought to be viral, and it **does not exhibit Koebner's phenomenon**.

Question 124: A patient with chronic plaque psoriasis develops an adverse response to therapy. Which response indicates treatment with hydroxychloroquine?

A. Sudden generalized flare (Correct Answer)
B. Localized plaque thickening
C. Palmoplantar involvement
D. Development of pustules

Explanation: ***Sudden generalized flare*** - Hydroxychloroquine, while sometimes used for **psoriatic arthritis**, is notorious for exacerbating cutaneous psoriasis, typically causing a **sudden generalized flare** of the disease. - This adverse effect is particularly significant in patients with plaque psoriasis, making hydroxychloroquine a **relative contraindication** in many cases. - This is the **most characteristic** adverse response to antimalarial therapy in psoriasis patients. *Localized plaque thickening* - This is a common feature of chronic plaque psoriasis itself and does not specifically indicate a response to hydroxychloroquine. - Plaque thickening can occur with disease progression or insufficient treatment but is not a recognized side effect of hydroxychloroquine. *Palmoplantar involvement* - **Palmoplantar psoriasis** is a specific morphological variant of the disease and is not a direct response to hydroxychloroquine treatment. - While it can be severe and difficult to treat, its presence does not signify a drug-induced phenomenon related to hydroxychloroquine. *Development of pustules* - While hydroxychloroquine can rarely trigger transformation to **pustular psoriasis**, this is less common than the typical presentation of acute generalized plaque exacerbation. - **Sudden generalized flare** of plaque psoriasis remains the most characteristic adverse response to hydroxychloroquine, making it the best answer among the options provided.

Question 125: A 50-year-old man with severe plaque psoriasis presents with worsening erythroderma and pustules despite recently starting cyclosporine. Labs show leukocytosis and elevated CRP. Most appropriate next step is:

A. Switch to methotrexate
B. Hospitalize for systemic therapy (Correct Answer)
C. Start oral retinoids
D. Continue cyclosporine and add topical steroids

Explanation: ***Hospitalize for systemic therapy*** - The presentation of **erythroderma** and **pustules** with **leukocytosis** and **elevated CRP** in a patient with severe psoriasis suggests **generalized pustular psoriasis** (von Zumbusch) or **erythrodermic psoriasis**, both life-threatening emergencies. - This requires **immediate hospitalization** for close monitoring, fluid and electrolyte management, temperature regulation, infection surveillance, and aggressive systemic therapy (often including biologics, systemic steroids, or combination therapy). - The severity with systemic inflammation mandates inpatient care rather than outpatient management. *Switch to methotrexate* - While **methotrexate** is effective for severe psoriasis, this patient is hemodynamically unstable with systemic inflammation requiring immediate inpatient monitoring and rapid intervention. - Methotrexate has a **slow onset of action** (weeks) and would not provide the urgent control needed for this acute emergency. - Outpatient drug switching is inappropriate for an unstable patient with erythroderma. *Start oral retinoids* - **Acitretin** is used for pustular psoriasis, but has **delayed onset** (2-3 months for full effect) and would be insufficient as monotherapy for this acute, life-threatening presentation. - The patient requires immediate hospitalization and faster-acting therapies, possibly including biologics or short-term systemic corticosteroids. *Continue cyclosporine and add topical steroids* - The disease is clearly not controlled on cyclosporine alone, and **topical steroids are inadequate** for managing widespread erythroderma with systemic inflammation. - This severe presentation requires **escalation to inpatient systemic therapy**, not continuation of an inadequate outpatient regimen.

Question 126: Skin biopsy shows psoriasiform hyperplasia with neutrophilic microabscesses in stratum corneum. Most likely diagnosis?

A. Psoriasis (Correct Answer)
B. Seborrheic dermatitis
C. Pityriasis rosea
D. Lichen planus

Explanation: ***Psoriasis*** - **Psoriasiform hyperplasia**, characterized by regular epidermal acanthosis and elongated rete ridges, is a classic histological feature of psoriasis. - The presence of **neutrophilic microabscesses (Munro microabscesses)** in the stratum corneum is a pathognomonic finding for psoriasis. *Seborrheic dermatitis* - Histologically, seborrheic dermatitis typically shows **irregular acanthosis** with parakeratosis and a **perivascular lymphocytic infiltrate**, but not regular psoriasiform hyperplasia or Munro microabscesses. - There may be *spongiosis* and neutrophils in the stratum corneum, but not the distinct microabscesses seen in psoriasis. *Pityriasis rosea* - Pityriasis rosea histology often reveals **focal parakeratosis**, **spongiosis**, and a **perivascular lymphocytic infiltrate** with extravasated red blood cells. - It does not demonstrate the characteristic regular psoriasiform hyperplasia or neutrophilic microabscesses of psoriasis. *Lichen planus* - Lichen planus is characterized by a **"sawtooth" rete ridge pattern**, a **band-like lymphocytic infiltrate** at the dermo-epidermal junction, and **colloid bodies (Civatte bodies)**. - It does not exhibit psoriasiform hyperplasia or neutrophilic microabscesses in the stratum corneum.

Question 127: Assertion: Vitamin D analogues are effective in psoriasis. Reason: They reduce keratinocyte proliferation

A. Both A & R true, R explains A (Correct Answer)
B. A false R true
C. Both A & R true, R doesn't explain A
D. A true R false

Explanation: ***Both A & R true, R explains A*** - **Vitamin D analogues** (e.g., calcipotriol) are a cornerstone treatment for psoriasis because they effectively modulate **keratinocyte proliferation** and differentiation. - Psoriasis is characterized by the **rapid overgrowth of keratinocytes**, and the antiproliferative effects of vitamin D analogues directly address this pathological hallmark. *A false R true* - This option is incorrect because both the assertion (Vitamin D analogues are effective in psoriasis) and the reason (They reduce keratinocyte proliferation) are individually true. - The effectiveness of vitamin D analogues in treating psoriasis is well-established in dermatological practice. *Both A & R true, R doesn't explain A* - This option is incorrect because the reduction of keratinocyte proliferation is precisely *how* vitamin D analogues exert their therapeutic effect in psoriasis. - The mechanism of action described in the reason directly explains the efficacy mentioned in the assertion. *A true R false* - This option is incorrect because the reason ("They reduce keratinocyte proliferation") is a fundamental and well-understood mechanism by which vitamin D analogues work in psoriasis. - Vitamin D analogues bind to vitamin D receptors in keratinocytes, influencing gene expression to inhibit their excessive growth.

Question 128: How does narrowband UVB therapy work in psoriasis?

A. Melanin synthesis
B. Collagen breakdown
C. Keratinocyte proliferation
D. T cell apoptosis (Correct Answer)

Explanation: ***T cell apoptosis*** - Narrowband UVB (NB-UVB) therapy primarily works by inducing **apoptosis (programmed cell death)** of activated **T-lymphocytes** in the psoriatic skin lesions. - By reducing the number of these inflammatory cells, NB-UVB helps to suppress the immune response that drives the **excessive keratinocyte proliferation** in psoriasis. *Melanin synthesis* - While UV radiation does stimulate **melanin synthesis**, leading to tanning, this is a secondary effect and not the primary therapeutic mechanism for psoriasis. - Increased melanin helps protect the skin from UV damage but does not directly treat the underlying pathology of psoriasis. *Collagen breakdown* - UV radiation, especially UVA, can contribute to **collagen breakdown** and photodamage over time, but this is an adverse effect, not a therapeutic mechanism for psoriasis. - Psoriasis treatment aims to normalize skin cell growth and reduce inflammation, not degrade collagen. *Keratinocyte proliferation* - Psoriasis is characterized by **accelerated keratinocyte proliferation**; NB-UVB therapy aims to *reduce* this proliferation, not promote it. - The mechanism by which NB-UVB achieves this reduction is primarily through its effects on immune cells, not by directly enhancing keratinocyte growth.

Question 129: A 25-year-old presents with silvery scales on elbows and knees. Likely diagnosis?

A. Psoriasis (Correct Answer)
B. Atopic dermatitis
C. Pityriasis rosea
D. Lichen planus

Explanation: ***Psoriasis*** - **Silvery scales** on **extensor surfaces** like elbows and knees are classic presentations of plaque psoriasis. - This chronic inflammatory skin condition is characterized by **accelerated epidermal turnover**. *Atopic dermatitis* - Typically presents as **eczematous lesions** characterized by **red, itchy, and often oozing or crusted patches**, mainly on flexural surfaces in adults. - It is strongly associated with a history of **allergies, asthma, or hay fever**. *Pityriasis rosea* - Usually starts with a **herald patch** followed by smaller, oval, pinkish-orange macules and patches with fine scales in a **Christmas tree pattern** on the trunk. - It is distinguished from psoriasis by its distribution and appearance of scales. *Lichen planus* - Characterized by **pruritic, purple, polygonal, planar papules and plaques** (the "6 P's") often with fine, white lacy streaks called **Wickham's striae**, typically affecting flexor surfaces, wrists, and oral mucosa. - It does not present with silvery scales on extensor surfaces.

Question 130: What histological feature is most characteristic of psoriasis?

A. Parakeratosis with retained nuclei in stratum corneum
B. Munro microabscesses in stratum corneum (Correct Answer)
C. Acanthosis with elongated rete ridges
D. Spongiform pustules of Kogoj in stratum spinosum

Explanation: ***Munro microabscesses in stratum corneum*** - Munro microabscesses are characteristic accumulations of **neutrophils** within the **stratum corneum** in psoriasis. - Their presence is a key **histological feature** used in the diagnosis of psoriasis. *Parakeratosis with retained nuclei in stratum corneum* - **Parakeratosis** (retained nuclei in the stratum corneum) is a feature of psoriasis but is **not specific** to it; it can be seen in other inflammatory skin conditions. - While present, it doesn't serve as the sole or most definitive characteristic feature differentiating psoriasis from other conditions. *Acanthosis with elongated rete ridges* - **Acanthosis** (epidermal hyperplasia) with elongated rete ridges is a prominent histological finding in psoriasis. - However, similar epidermal changes can be observed in various other chronic inflammatory skin conditions, making it **less specific** than Munro microabscesses. *Spongiform pustules of Kogoj in stratum spinosum* - **Spongiform pustules of Kogoj** are collections of neutrophils predominantly found in the **stratum spinosum**. - While associated with some forms of psoriasis, particularly **pustular psoriasis**, they are not considered the universally characteristic feature of typical plaque psoriasis.

Question 131: A 54-year-old man presents with well-demarcated, erythematous plaques covered with silvery-white scales on the extensor surfaces of his elbows and knees. What is the most likely diagnosis?

A. Pityriasis rosea
B. Psoriasis (Correct Answer)
C. Eczema
D. Lichen planus

Explanation: ***Psoriasis*** - **Psoriasis** classically presents with **scaly plaques** that often appear on the **extensor surfaces** such as the elbows and knees. - The scales are typically silvery-white and can be itchy or painful, consistent with the characteristic presentation of chronic plaque psoriasis. *Pityriasis rosea* - This condition presents with a **herald patch** followed by smaller, oval, pinkish-red patches with fine scales, often distributed in a **Christmas tree pattern** on the trunk. - It primarily affects the trunk and proximal extremities, rarely involving the extensor surfaces in the same way as psoriasis. *Eczema* - **Eczema**, particularly atopic dermatitis, typically presents with **itchy, erythematous patches** that are often ill-defined and can be dry or weeping. - While it can occur on extensor surfaces, it is more commonly found on flexural surfaces in adults and lacks the distinct, thick silvery scales characteristic of psoriasis. *Lichen planus* - **Lichen planus** is characterized by **pruritic, purple, polygonal, planar papules and plaques** (**the 6 P's**). - It usually affects the flexural surfaces, wrists, ankles, and oral mucosa, rather than predominantly presenting as scaly plaques on extensor surfaces.

Question 132: A 40-year-old male presents with erythematous scaly lesions on the extensor surfaces of his elbows and knees. The clinical diagnosis is confirmed by which sign?

A. Auspitz sign (Correct Answer)
B. KOH smear
C. Tzanck smear
D. Skin biopsy

Explanation: ***Auspitz sign*** - The presence of **erythematous scaly lesions on extensor surfaces** is highly suggestive of **psoriasis**. - The **Auspitz sign** is specific to psoriasis; it refers to pinpoint bleeding after scaling is removed due to exposure of dilated capillaries in dermal papillae. *KOH smear* - A **KOH smear** is used to identify fungal elements in skin, hair, or nails. - It would be relevant if fungal infection were suspected, but not for the clinical picture of psoriasis. *Tzanck smear* - A **Tzanck smear** is used to detect multinucleated giant cells characteristic of herpes simplex or varicella-zoster virus infections. - It is not indicated for the diagnosis of psoriasis. *Skin biopsy* - While a **skin biopsy** can confirm psoriasis, it is typically reserved for atypical presentations or equivocal clinical findings. - The **Auspitz sign** provides a more immediate and clinically specific diagnostic confirmation for classic psoriasis lesions.

Question 133: A 50-year-old female presents with thickened, hyperkeratotic plaques on her palms and soles, accompanied by a positive Auspitz sign. What is the diagnosis?

A. Palmoplantar psoriasis (Correct Answer)
B. Eczema
C. Lichen planus
D. Pityriasis rubra pilaris

Explanation: ***Palmoplantar psoriasis*** - This condition is characterized by **thickened, hyperkeratotic plaques** specifically on the **palms and soles**. - A **positive Auspitz sign** (pinpoint bleeding after scaling is removed) is a classic finding in **psoriasis**, further supporting this diagnosis. *Eczema* - While eczema can affect the palms and soles (dyshidrotic eczema), it typically presents with **vesicles, intense itching, redness**, and less defined plaques. - The **Auspitz sign is not present** in eczema. *Lichen planus* - Characterized by **pruritic, purple, polygonal, planar papules and plaques** (the 6 Ps), often on the flexural surfaces, wrists, and ankles. - It does not typically present with the specific hyperkeratotic plaques of palmoplantar psoriasis, nor does it have a positive Auspitz sign. *Pityriasis rubra pilaris* - This condition presents with **follicular papules** that coalesce into **salmon-colored plaques** with islands of unaffected skin. - It often involves generalized erythema and scaling but does not typically present as sharply demarcated hyperkeratotic plaques on the palms and soles, nor does it have a positive Auspitz sign.

Question 134: A 60-year-old woman presents with pruritic, erythematous plaques on her elbows and knees. A skin biopsy shows hyperkeratosis, parakeratosis, and neutrophils in the stratum corneum. What is the diagnosis?

A. Psoriasis (Correct Answer)
B. Atopic dermatitis
C. Lichen planus
D. Seborrheic dermatitis

Explanation: ***Psoriasis*** - The presentation of **pruritic, erythematous plaques** on the **extensor surfaces** (elbows and knees) is classic for **psoriasis**. - Histopathological findings of **hyperkeratosis**, **parakeratosis**, and **neutrophils in the stratum corneum** (Munro microabscesses) are characteristic of psoriasis. *Atopic dermatitis* - Typically presents with **pruritic, eczematous lesions** in flexural areas (e.g., antecubital and popliteal fossae), not usually on extensor surfaces. - Histology would show **spongiosis** (intercellular edema in the epidermis) and **lymphocytic infiltrate**, not prominent neutrophils in the stratum corneum. *Lichen planus* - Characterized by **pruritic, polygonal, purple, planar papules and plaques** (the "6 Ps"), often affecting the wrists, ankles, and oral mucosa. - Histology typically reveals a **sawtooth rete ridge pattern** and a **band-like lymphocytic infiltrate** at the dermo-epidermal junction. *Seborrheic dermatitis* - Usually presents with **greasy, yellowish scales** on erythematous skin in areas rich in sebaceous glands, such as the scalp, face, and chest. - Histology would show **spongiosis**, **psoriasiform hyperplasia**, and a **perivascular lymphocytic infiltrate** with **neutrophils around follicular openings**.

Question 135: A 45-year-old woman presents with chronic plaques on her elbows and knees accompanied by silvery scales. What is the most appropriate first-line treatment?

A. Topical steroids (Correct Answer)
B. Oral antibiotics
C. Phototherapy
D. Systemic retinoids

Explanation: **Topical Steroids** - For localized, chronic plaques like those seen in **psoriasis** on the elbows and knees, **topical corticosteroids** are the first-line treatment due to their anti-inflammatory properties. - They help reduce **redness, scaling, and itching**, providing effective symptom control for mild to moderate cases. *Oral Antibiotics* - **Oral antibiotics** are used to treat bacterial infections and have no role in the management of psoriasis, which is an **autoimmune inflammatory condition**. - There is no indication of infection (e.g., pus, fever, rapidly spreading cellulitis) in this presentation. *Phototherapy* - **Phototherapy** (e.g., UVB or PUVA) is an effective treatment for widespread or more severe psoriasis, but it is typically reserved when **topical therapies** are insufficient. - It is not usually considered the **first-line treatment** for localized plaques on elbows and knees. *Systemic Retinoids* - **Systemic retinoids** (like acitretin) are potent medications used for severe, widespread, or disabling psoriasis, especially pustular or erythrodermic forms. - They have significant **side effects** and require careful monitoring, making them unsuitable as a first-line treatment for localized plaques.

Question 136: A 50-year-old man presents with red, scaly patches on his scalp that bleed when scratched. This is indicative of which condition?

A. Psoriasis (Correct Answer)
B. Seborrheic dermatitis
C. Tinea capitis
D. Lichen planus

Explanation: ***Psoriasis*** - **Red, scaly patches** on the scalp, especially those that **bleed when scratched** (Auspitz sign), are classic signs of **psoriasis**. - Psoriasis is a **chronic autoimmune** skin condition characterized by accelerated skin cell turnover. *Seborrheic dermatitis* - Presents with **greasy, yellowish scales** and redness, often found in areas with high sebaceous gland activity like the scalp. - Unlike psoriasis, it typically does not exhibit significant bleeding when scratched. *Tinea capitis* - This is a **fungal infection** of the scalp, characterized by **scaly patches**, **hair loss**, and sometimes **black dots** from broken hairs. - It is often associated with itching but usually does not involve the prominent bleeding seen in psoriasis. *Lichen planus* - Characterized by **purplish, polygonal, planar, pruritic papules** and plaques, often on the flexor surfaces, but can affect the scalp. - Scalp involvement, known as lichen planopilaris, typically leads to **scarring alopecia** and does not present with red, scaly patches that bleed easily upon scratching.

Question 137: A 40-year-old male presents with chronic, relapsing pustular eruptions on the palms and soles, along with a history of smoking. What is the most likely diagnosis?

A. Pustular psoriasis
B. Dyshidrotic eczema
C. Palmoplantar pustulosis (Correct Answer)
D. Contact dermatitis

Explanation: ***Palmoplantar pustulosis*** - This condition is characterized by **chronic, relapsing sterile pustules** localized to the **palms and soles**, often associated with a history of **smoking**. - It is now considered a **distinct entity** separate from psoriasis, though it was historically classified as a variant of pustular psoriasis. The strong smoking association and typical palmoplantar distribution are key diagnostic features. *Pustular psoriasis* - Generalized pustular psoriasis presents with **widespread pustules** on erythematous skin beyond the palms and soles and can be accompanied by systemic symptoms such as fever and malaise. - Unlike palmoplantar pustulosis, it typically has a more acute presentation and lacks the exclusive palmoplantar distribution. *Dyshidrotic eczema* - Characterized by **deep-seated vesicles** (not true pustules) on the palms and soles, often intensely itchy. - Lesions are primarily **vesicular** before they rupture or dry, and lack the strong association with **smoking** seen in palmoplantar pustulosis. *Contact dermatitis* - Results from an **allergic or irritant reaction** to an external substance, leading to eczema, erythema, and vesicles in areas of contact. - Would typically have an **identifiable trigger** and would not primarily manifest as **sterile pustules** recurring chronically without clear exposure history.

Question 138: A 60-year-old woman presents with red, scaly patches on her arms that bleed easily when scratched. This is a classic sign of which condition?

A. Psoriasis (Correct Answer)
B. Seborrheic dermatitis
C. Actinic keratosis
D. Lichen planus

Explanation: ***Psoriasis*** - **Red, scaly patches** that **bleed easily when scratched** (known as the **Auspitz sign**) are **pathognomonic** for psoriasis. - Psoriasis is a **chronic autoimmune** skin condition characterized by accelerated skin cell turnover. *Seborrheic dermatitis* - Characterized by **greasy, yellow scales** on erythematous skin, often in areas with high sebaceous gland activity like the scalp, face, and chest. - It is typically **not associated with the Auspitz sign** or easily bleeding lesions. *Actinic keratosis* - Presents as **rough, scaly patches** on sun-exposed skin and is considered a **precancerous lesion**. - While scaly, it generally does not exhibit the classic vivid redness or **Auspitz sign** seen in psoriasis. *Lichen planus* - Characterized by **pruritic, purple, polygonal, planar papules** and plaques, often on the flexor surfaces of the wrists and ankles. - It may cause Lacy white patterns on mucous membranes (Wickham's striae) and **does not typically bleed easily** when scratched.

Question 139: Multiple psoriatic lesions on hands. Treatment of choice is?

A. NBUVB
B. Systemic methotrexate
C. Systemic steroids
D. Topical steroids with salicylic acid (Correct Answer)

Explanation: ***Topical steroids with salicylic acid*** - For **localized psoriasis**, such as lesions primarily on the hands, **topical corticosteroids** are the first-line treatment due to their anti-inflammatory effects. - **Salicylic acid** helps with **keratolysis**, reducing the scaling associated with psoriatic plaques, thereby improving penetration of the steroid. *NBUVB* - **Narrowband UVB (NBUVB)** therapy is more suitable for **widespread plaque psoriasis** rather than localized lesions on the hands. - It requires frequent clinic visits and may not be practical or cost-effective for small, confined areas. *Systemic methotrexate* - **Systemic methotrexate** is reserved for **moderate to severe psoriasis** or psoriatic arthritis that is unresponsive to topical treatments or phototherapy. - Its use carries risks of **hepatotoxicity** and **bone marrow suppression**, making it inappropriate for localized disease. *Systemic steroids* - **Systemic corticosteroids** are generally avoided in psoriasis due to the risk of **rebound flares** or exacerbation of the disease upon withdrawal. - They are typically reserved for severe, acute flares and used with extreme caution, often as a bridge therapy.

Question 140: What is the treatment of choice for erythrodermic psoriasis?

A. Acitretin
B. Methotrexate (Correct Answer)
C. Prednisone
D. Biologics

Explanation: ***Methotrexate*** - **Methotrexate** is considered the first-line systemic treatment for erythrodermic psoriasis in most standard guidelines and medical textbooks. - It is an immunosuppressant that works by inhibiting folate metabolism, thereby reducing keratinocyte hyperproliferation and inflammatory processes. - It has an established efficacy profile, relatively rapid onset of action (4-8 weeks), and is cost-effective and widely accessible. *Prednisone* - While systemic corticosteroids like **prednisone** can acutely suppress inflammation, they are **contraindicated** in erythrodermic psoriasis due to high risk of **rebound flares** and potential worsening upon withdrawal. - Long-term systemic corticosteroid use carries significant side effects including osteoporosis, hypertension, and diabetes. *Acitretin* - **Acitretin** is an oral retinoid that can be effective for erythrodermic psoriasis, but has a **slower onset of action** (2-3 months) compared to methotrexate. - It carries significant **teratogenic risks** requiring strict contraception for 2-3 years after discontinuation in women of childbearing potential. - Side effects include mucocutaneous dryness, hyperlipidemia, and hepatotoxicity. *Biologics* - **Biologics** (anti-TNF, anti-IL-17, anti-IL-23 agents) are highly effective for severe psoriasis including erythrodermic forms. - They are typically considered **second-line** agents due to higher cost, limited availability in resource-constrained settings, need for parenteral administration, and potential for serious infections. - While increasingly used in modern practice, **methotrexate** remains the standard first-line systemic agent in most treatment protocols.

Question 141: Woronoff's ring is specifically associated with which skin condition?

A. Lichen planus
B. Pityriasis rosea
C. Pemphigus
D. Psoriasis (Correct Answer)

Explanation: ***Psoriasis*** - **Woronoff's ring** is a characteristic pale, blanching ring that can appear around resolving psoriatic plaques, especially after phototherapy or topical treatments. - It results from a local vasoconstriction or altered vascular response in the lesional skin as inflammation subsides. *Lichen planus* - Characterized by **purple, polygonal, pruritic papules and plaques**, often with **Wickham's striae** (fine white lines). - It does not present with Woronoff's ring. *Pityriasis rosea* - Presents with a **herald patch** followed by widespread small, oval, faint reddish-brown lesions arranged in a **"Christmas tree" pattern** on the trunk. - This condition is self-limiting and not associated with Woronoff's ring. *Pemphigus* - A group of **autoimmune blistering diseases** caused by antibodies against desmogleins, leading to **flaccid blisters** that rupture easily. - Clinical signs include Nikolsky's sign, but not Woronoff's ring.

Question 142: Psoriatic arthritis most commonly involves which joint -

A. Distal interphalangeal joint (Correct Answer)
B. Proximal interphalangeal joint
C. Wrist joint
D. Metacarpophalangeal joint

Explanation: ***Distal interphalangeal joint*** - Psoriatic arthritis has a predilection for the **distal interphalangeal (DIP) joints**, a feature that helps distinguish it from other inflammatory arthropathies. - Involvement of the DIP joints often correlates with **nail psoriasis** and can lead to characteristic **"sausage digits"** (dactylitis). *Proximal interphalangeal joint* - While **proximal interphalangeal (PIP) joints** can be affected in psoriatic arthritis, it is not the most common or characteristic pattern of involvement. - PIP joint involvement is more typically associated with **rheumatoid arthritis**, although it can occur in a polyarticular presentation of psoriatic arthritis. *Wrist joint* - The **wrist joint** can be affected in psoriatic arthritis, particularly in more severe or polyarticular forms, but it is not the most common initial presentation. - Wrist involvement can lead to significant pain and functional impairment but is less specific to psoriatic arthritis compared to DIP joint involvement. *Metacarpophalangeal joint* - **Metacarpophalangeal (MCP) joints** are also less commonly affected as the primary site in psoriatic arthritis compared to the DIP joints. - MCP joint involvement is a hallmark of **rheumatoid arthritis**, where it often presents with symmetrical inflammation.

Question 143: Keratodermic sandals are associated with which of the following conditions?

A. Lichen planus
B. Psoriasis
C. Pityriasis rubra pilaris (Correct Answer)
D. Pityriasis rosea

Explanation: ***Pityriasis rubra pilaris*** - **Keratodermic sandals** describe the characteristic **thickening and orange-red discoloration of the palms and soles** seen in pityriasis rubra pilaris. - This condition also typically presents with **follicular papules** and areas of normal skin (islands of sparing) amidst generalized erythema. *Pityriasis rosea* - Characterized by a **herald patch** followed by an eruption of oval, erythematous, scaly patches on the trunk and proximal extremities, often arranged in a **Christmas tree pattern**. - It does not involve significant palmar or plantar hyperkeratosis. *Lichen planus* - Manifests as **pruritic, purple, polygonal, planar papules and plaques** (the 6 P's), often affecting the wrists, ankles, and oral mucosa. - While it can involve nail changes and sometimes hyperkeratosis, the specific "keratodermic sandals" pattern is not characteristic. *Psoriasis* - Typically presents with well-demarcated, erythematous plaques covered by **silvery scales**, commonly on extensor surfaces, scalp, and nails. - Although palmoplantar psoriasis can occur, it's distinct from the diffuse, orange-red hyperkeratosis described as keratodermic sandals in pityriasis rubra pilaris.

Question 144: HLA-Cw6 is associated with

A. Behcet's disease
B. Pemphigus vulgaris
C. Psoriasis vulgaris (Correct Answer)
D. Myasthenia gravis

Explanation: ***Psoriasis vulgaris*** - **HLA-Cw6** is the **strongest genetic risk factor** associated with an increased susceptibility to psoriasis vulgaris, particularly early-onset forms. - Its presence is linked to a more severe and widespread presentation of the disease. *Myasthenia gravis* - This autoimmune disorder is primarily associated with **HLA-DR3** and **HLA-B8**, and autoantibodies against the acetylcholine receptor. - While other HLA alleles may be involved, **HLA-Cw6** is not a primary or strong genetic association for myasthenia gravis. *Behcet's disease* - **HLA-B51** is the most significant genetic association with Behcet's disease, particularly in populations of Middle Eastern and East Asian descent. - Symptoms include **recurrent oral and genital ulcers**, **uveitis**, and skin lesions. *Pemphigus vulgaris* - This autoimmune blistering disease is strongly associated with **HLA-DR4** and **HLA-DRw6**, especially in individuals of Jewish descent. - It involves autoantibodies targeting **desmoglein 1 and 3**, leading to acantholysis within the epidermis.

Question 145: The Grattage test is used to diagnose which of the following conditions?

A. Tinea capitis
B. Lichen planus
C. Pemphigus vulgaris
D. Psoriasis (Correct Answer)

Explanation: ***Psoriasis*** - The **Grattage test** (candle grease sign) involves **scraping the psoriatic lesion** to reveal characteristic features - First reveals **fine, silvery-white scales** resembling candle wax - Further scraping exposes **pinpoint bleeding points** (**Auspitz sign**) due to exposure of dilated capillaries in dermal papillae - This combination is **pathognomonic for psoriasis** and helps differentiate it from other scaly dermatoses *Tinea capitis* - A **fungal infection of the scalp** caused by dermatophytes - Diagnosed by **KOH mount** (showing fungal hyphae), **fungal culture**, and sometimes **Wood's lamp examination** - The Grattage test is not used for diagnosing fungal infections *Lichen planus* - Characterized by **purplish, polygonal, flat-topped, pruritic papules and plaques** - Surface shows **Wickham's striae** (fine white lines) - Diagnosis is **clinical**, supported by **skin biopsy** showing band-like lymphocytic infiltrate and sawtooth rete ridges - The Grattage test is not applicable *Pemphigus vulgaris* - A severe **autoimmune blistering disorder** with **suprabasal acantholysis** - Presents with **flaccid bullae** that rupture easily, leaving erosions - Diagnosed by **skin biopsy**, **direct immunofluorescence** (intercellular IgG and C3 deposits), and **Nikolsky's sign** (positive) - The Grattage test is not used for bullous disorders

Question 146: In which of the following conditions is the Koebner phenomenon most commonly observed?

A. Psoriasis (Correct Answer)
B. Lichen planus
C. All of the options
D. Viral warts

Explanation: ***Correct: Psoriasis*** - **Psoriasis** is the **most classic and commonly cited example** of the Koebner phenomenon (isomorphic response) - New psoriatic plaques characteristically develop at sites of cutaneous trauma, scratches, or surgical incisions in 25-50% of psoriasis patients - This is a **pathognomonic feature** frequently tested in competitive exams and considered the prototype condition for demonstrating this phenomenon - The mechanism involves inflammatory cascades triggered by trauma in genetically predisposed skin *Incorrect: Lichen planus* - While lichen planus does exhibit the Koebner phenomenon with purplish polygonal papules appearing along scratch lines, it is **less commonly observed** compared to psoriasis - Seen in approximately 10-25% of lichen planus cases - Not considered the primary example when teaching about Koebner phenomenon *Incorrect: Viral warts* - Viral warts can demonstrate **pseudo-Koebner phenomenon** where new warts form along trauma lines due to viral inoculation - This is more accurately described as **autoinoculation** rather than true isomorphic response - Less commonly discussed in the context of classic Koebner phenomenon compared to psoriasis *Incorrect: All of the options* - While all three conditions can show Koebner-like responses, the question asks for "**most commonly observed**" - Psoriasis remains the **gold standard** and most frequently encountered example in clinical practice and medical literature

Question 147: Which HLA allele is most strongly associated with psoriasis?

A. HLA B27
B. HLA DR4
C. HLA CW6 (Correct Answer)
D. HLA B8

Explanation: ***HLA CW6*** - **HLA-Cw6** is the most strongly associated **HLA allele** with **psoriasis**, particularly with Type I (early-onset) psoriasis. - Its presence is linked to a more severe and widespread form of the disease. *HLA B27* - **HLA-B27** is strongly associated with **spondyloarthropathies** like **ankylosing spondylitis** and **reactive arthritis**, not directly with psoriasis itself, although it can be present in psoriatic arthritis. - Its primary role is in conditions affecting the **axial skeleton** and **entheses**. *HLA DR4* - **HLA-DR4** is a significant genetic marker for **rheumatoid arthritis** and **Type 1 diabetes**. - It is not directly associated with the pathogenesis of psoriasis. *HLA B8* - **HLA-B8** is associated with various autoimmune diseases such as **celiac disease**, **myasthenia gravis**, and **lupus erythematosus**. - It does not have a direct or strong association with psoriasis.

Question 148: Which of the following features is characteristic of psoriasis?

A. Grenz zone
B. Micro-Munro's abscess (Correct Answer)
C. Hyperkeratosis
D. Pautrier's microabscess

Explanation: ***Micro-Munro's abscess*** - These are small collections of **neutrophils in the stratum corneum** and represent a **specific histological hallmark of psoriasis**. - Also known as **Munro microabscesses**, they are formed due to neutrophil migration into the upper epidermis in response to inflammatory signals. - This is a **characteristic and diagnostic feature** that helps differentiate psoriasis from other papulosquamous disorders. *Hyperkeratosis* - While hyperkeratosis (thickening of stratum corneum) is present in psoriasis and causes the silvery scales, it is **not specific** to psoriasis. - Hyperkeratosis occurs in many dermatological conditions including **eczema, lichen planus, ichthyosis**, and other keratinization disorders. - It is a general finding rather than a characteristic diagnostic feature. *Grenz zone* - The **Grenz zone** is a clear, narrow band of unaffected dermis between the epidermis and underlying dermal infiltrate. - This feature is characteristic of conditions like **granulomatous diseases** and **mycosis fungoides**, not psoriasis. - In psoriasis, the dermal infiltrate typically extends to the dermoepidermal junction without a clear zone. *Pautrier's microabscess* - These are **intraepidermal collections of atypical lymphocytes** and are a diagnostic feature of early-stage **mycosis fungoides** (cutaneous T-cell lymphoma). - They are not seen in psoriasis; psoriasis involves **neutrophils** (Munro microabscesses), not lymphocytic collections.

Question 149: Auspitz's sign is characteristically seen in

A. Plaque Psoriasis (Correct Answer)
B. Inverse Psoriasis
C. Pustular Psoriasis
D. Lichen Planus (flat-topped, purple papules)

Explanation: ***Plaque Psoriasis*** - **Auspitz's sign** is the appearance of pinpoint bleeding after the removal of scales from a psoriatic plaque, a classic finding in **plaque psoriasis**. - This phenomenon is due to the thinning of the epidermis over elongated and dilated dermal papillae, making the superficial capillaries prone to rupture. *Pustular Psoriasis* - This form of psoriasis is characterized by the presence of sterile **pustules** on erythematous skin, either localized or generalized. - While it is a type of psoriasis, Auspitz's sign is not its characteristic feature; rather, the presence of pustules defines this variant. *Inverse Psoriasis* - Inverse psoriasis typically affects **skin folds** (e.g., axillae, groin, inframammary regions) and presents as smooth, erythematous patches without the characteristic scaling seen in plaque psoriasis. - Due to the absence of thick scales, Auspitz's sign is generally not observed in inverse psoriasis. *Lichen Planus (flat-topped, purple papules)* - Lichen planus is an inflammatory condition characterized by **pruritic, polygonal, planar, purple papules** and plaques, often with **Wickham's striae**. - It does not involve the epidermal scaling and capillary changes that lead to Auspitz's sign.

Question 150: Which type of psoriasis is commonly seen in children and may follow a streptococcal sore throat?

A. Pustular psoriasis
B. Stable plaque psoriasis
C. Arthropathic psoriasis
D. Guttate psoriasis (Correct Answer)

Explanation: ***Guttate psoriasis*** - This form of psoriasis is characterized by **small, drop-like lesions** that often appear suddenly over the trunk and extremities. - It is frequently precipitated by an **upper respiratory infection**, most commonly a **streptococcal sore throat**, particularly in children and young adults. *Pustular psoriasis* - This is a rare, severe form characterized by widespread **sterile pustules** on red, inflamed skin. - It is not typically associated with streptococcal infections or common in children as an initial presentation. *Stable plaque psoriasis* - This is the most common form, presenting with **well-demarcated, erythematous plaques** covered with silvery scales. - It usually has a **chronic course** and is not typically triggered by acute infections like strep throat. *Arthropathic psoriasis* - This is a form of **psoriatic arthritis** where psoriasis is accompanied by inflammation of the joints. - While it can occur in children, its hallmark is joint involvement, and it is not primarily associated with preceding streptococcal infections.

Question 151: A patient with psoriasis who was started on systemic steroids develops generalized pustules all over the body after stopping treatment. What is the most likely cause?

A. Bacterial infection
B. Septicemia
C. Pustular psoriasis due to steroid withdrawal (Correct Answer)
D. Drug-induced pustular psoriasis

Explanation: ***Pustular psoriasis due to steroid withdrawal*** - **Systemic steroid withdrawal** can precipitate a severe flare of psoriasis, often leading to generalized **pustular psoriasis**. - This is a well-known phenomenon where the suppression of the immune system by steroids is abruptly removed, causing a rebound inflammatory response. *Drug-induced pustular psoriasis* - While certain drugs can induce pustular psoriasis, the scenario specifically highlights the **cessation of systemic steroids** as the trigger. - This option doesn't pinpoint the direct causal effect of stopping the medication. *Bacterial infection* - Although pustules can be associated with bacterial infections, the **generalized nature** and history of **steroid withdrawal** in a patient with psoriasis make an infectious cause less likely as the primary trigger. - A bacterial infection would typically present with signs of local infection (e.g., warmth, tenderness, fever) alongside the pustules, which are not exclusively mentioned here. *Septicemia* - **Septicemia** is a severe bloodstream infection and would present with systemic signs of illness such as high fever, chills, hypotension, and organ dysfunction, which are not described. - While pustules can sometimes occur in severe infections, the clinical context strongly points to a dermatological reaction to medication changes, not a systemic infection.

Question 152: Which of the following conditions is characterized by specific nail changes such as pitting, onycholysis, and oil spots?

A. Lichen planus
B. Psoriasis (Correct Answer)
C. Darier disease
D. Onychomycosis

Explanation: ***Psoriasis*** - **Psoriasis** characteristically causes several specific nail changes, including **pitting**, **onycholysis** (separation of the nail plate from the nail bed), and **oil spots** (yellow-brown discoloration resembling an oil drop under the nail). - These nail manifestations are often indicative of underlying psoriatic disease, even in the absence of extensive skin lesions. *Lichen planus* - **Lichen planus** can affect the nails, causing longitudinal ridging, thinning, and sometimes pterygium formation, but typically not pitting, onycholysis, or oil spots. - In severe cases, it can lead to permanent nail loss or scarring. *Darier disease* - **Darier disease** (keratosis follicularis) is characterized by specific nail findings such as longitudinal red and white streaks, V-shaped notching at the distal nail edge, and subungual hyperkeratosis. - It does not present with the classic triad of pitting, onycholysis, and oil spots. *Onychomycosis* - **Onychomycosis** is a fungal infection of the nail that typically causes thickening, discoloration (yellow, brown, white), and crumbling of the nail plate. - While it can cause onycholysis, it does not typically produce pitting or oil spots, which are more specific to psoriasis.

Question 153: What is Woronoff's ring?

A. A ring of lesions seen in flexural areas when hands are rested on the trunk.
B. An annular hypopigmented ring surrounding lesions of psoriasis. (Correct Answer)
C. Ring-shaped pruritic lesions on the dorsum of the foot.
D. An annular erythematous rash around the eyes in allergic dermatitis.

Explanation: **An annular hypopigmented ring surrounding lesions of psoriasis.** - Woronoff's ring is a **clinical finding** characterized by a pale, **hypopigmented halo** or ring that appears around resolving psoriatic plaques. - It is thought to reflect a local release of **prostaglandins** or other modulators that inhibit melanocyte activity or cause vasoconstriction. *A ring of lesions seen in flexural areas when hands are rested on the trunk.* - This description does not correspond to Woronoff's ring and is inconsistent with its typical presentation as a **halo around psoriatic lesions**. - No specific dermatological condition is commonly defined by "a ring of lesions seen in flexural areas when hands are rested on the trunk." *Ring-shaped pruritic lesions on the dorsum of the foot.* - This describes a symptom of various dermatophyte infections (like **tinea pedis**) or other inflammatory conditions, which is distinct from Woronoff's ring. - Woronoff's ring is specifically associated with **psoriasis resolution**, not primary pruritic foot lesions. *An annular erythematous rash around the eyes in allergic dermatitis.* - This description is typical of an **allergic contact dermatitis** or periorbital dermatitis, characterized by **erythema** and **pruritus** in a ring distribution around the eyes. - Woronoff's ring is neither erythematous nor associated with allergic reactions, but rather with the **resolution phase of psoriasis**.

Question 154: Acrodermatitis continua of Hallopeau is due to which of the following?

A. Zinc toxicity
B. Zinc deficiency
C. Collodion baby
D. Pustular psoriasis (Correct Answer)

Explanation: ***Pustular psoriasis*** - **Acrodermatitis continua of Hallopeau** is considered a severe, chronic, and localized variant of **pustular psoriasis** that primarily affects the distal extremities, particularly the nail beds and fingertips. - It involves recurrent outbreaks of **sterile pustules** that can lead to onychodystrophy, anonychia, and bone resorption. *Zinc toxicity* - **Zinc toxicity** can cause symptoms such as nausea, vomiting, abdominal pain, and copper deficiency, but it is not linked to acrodermatitis continua of Hallopeau. - Dermatological manifestations of zinc toxicity are generally not pustular or associated with nail and digit changes seen in this condition. *Zinc deficiency* - **Zinc deficiency** can lead to acrodermatitis enteropathica, a condition characterized by periorificial and acral dermatitis, alopecia, and diarrhea. - While it involves skin involvement in similar areas, the primary lesions are **eczematous and psoriasiform**, not typically sterile pustules as seen in acrodermatitis continua. *Collodion baby* - **Collodion baby** refers to a newborn covered by a taut, shiny membrane that resembles plastic wrap, typically associated with congenital ichthyoses. - It is a specific neonatal presentation of a skin barrier defect and is not related to acrodermatitis continua of Hallopeau or pustular skin conditions.

Question 155: Tildrakizumab was approved in March 2018 for what indication?

A. Psoriasis (Correct Answer)
B. HIV
C. Hepatitis C
D. Rheumatoid arthritis

Explanation: ***Psoriasis*** - **Tildrakizumab** (Ilumya) is an **IL-23 inhibitor** specifically approved for the treatment of **moderate to severe plaque psoriasis** in adults. - It targets the **p19 subunit of IL-23**, which plays a key role in the inflammatory cascade of psoriasis. *HIV* - HIV treatment involves **antiretroviral therapy (ART)**, which targets various stages of the viral life cycle. - Tildrakizumab has no known efficacy against **HIV infection**. *Rheumatoid arthritis* - Management of **rheumatoid arthritis** typically involves **DMARDs (disease-modifying antirheumatic drugs)**, biologics like **TNF inhibitors**, or **IL-6 inhibitors**. - While IL-23 is involved in inflammation, tildrakizumab is not indicated for **rheumatoid arthritis**. *Hepatitis C* - **Hepatitis C** is treated with direct-acting antiviral (DAA) medications that target viral enzymes. - Tildrakizumab is an immunomodulator and has no role in the treatment of **Hepatitis C**.

Question 156: Secukinumab is used in:

A. Psoriasis (Correct Answer)
B. Colorectal carcinoma
C. Breast cancer
D. Rheumatoid arthritis

Explanation: ***Psoriasis*** - **Secukinumab** is a monoclonal antibody that targets **interleukin-17A (IL-17A)**, a cytokine crucial in the pathogenesis of psoriasis. - It is approved for the treatment of **moderate to severe plaque psoriasis**, psoriatic arthritis, and ankylosing spondylitis. *Colorectal carcinoma* - **Secukinumab** is not used in the treatment of colorectal carcinoma; different classes of drugs like **chemotherapy**, **targeted therapies**, and **immunotherapy** (e.g., PD-1 inhibitors for MSI-high status) are employed. - Colorectal cancer treatment focuses on blocking pathways specific to cancer cell growth and survival, not IL-17A. *Breast cancer* - **Secukinumab** has no role in the treatment of breast cancer, which is managed with therapies such as **hormonal therapy**, **chemotherapy**, **HER2-targeted therapy**, and PARP inhibitors. - Breast cancer involves distinct molecular pathways and immune responses unrelated to IL-17A. *Rheumatoid arthritis* - While **rheumatoid arthritis** is an inflammatory condition, **secukinumab** is not a primary or approved treatment for it; other biologics like **TNF inhibitors**, **IL-6 inhibitors**, or **JAK inhibitors** are commonly used. - The inflammatory cascade in rheumatoid arthritis involves different key cytokines and cellular processes compared to those targeted by secukinumab.

Practice by Chapter

Pathophysiology of Psoriasis

Practice Questions

Psoriasis Vulgaris

Practice Questions

Guttate Psoriasis

Practice Questions

Erythrodermic Psoriasis

Practice Questions

Pustular Psoriasis

Practice Questions

Palmoplantar Psoriasis

Practice Questions

Nail Psoriasis

Practice Questions

Scalp Psoriasis

Practice Questions

Psoriatic Arthritis

Practice Questions

Topical Therapy for Psoriasis

Practice Questions

Systemic Therapy for Psoriasis

Practice Questions

Phototherapy and Biologics for Psoriasis

Practice Questions

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Psoriasis — MCQs

Psoriasis — MCQs

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