Dermatology
9 questionsTreatment of dermatitis herpetiformis:
What is the most common trigger associated with erythema multiforme?
Acantholysis is not seen in:
Nikolsky's sign is associated with which of the following conditions?
What is the treatment of choice for lichen planus?
The Grattage test is used to diagnose which of the following conditions?
Most common metal in contact allergic dermatitis is?
A 25-year-old patient presents with chronic itchy, erythematous skin lesions on the flexural areas that have been recurring since childhood. The patient has a family history of asthma. Which of the following is the most important diagnostic criterion for the most likely diagnosis?
Which of the following conditions does NOT cause nail pitting?
NEET-PG 2013 - Dermatology NEET-PG Practice Questions and MCQs
Question 1221: Treatment of dermatitis herpetiformis:
- A. Dapsone
- B. Sulfonamide
- C. Gluten-free diet
- D. All of the options (Correct Answer)
Explanation: ***All of the options*** - **Dermatitis herpetiformis (DH)** is a chronic, intensely itchy blistering skin condition associated with **celiac disease**. - Effective management involves both a **gluten-free diet** to address the underlying autoimmune process and medications like **dapsone** or **sulfonamides** for symptomatic relief. *Gluten-free diet* - A strict **gluten-free diet** is crucial for long-term management as it addresses the underlying small intestinal enteropathy associated with **celiac disease** and **dermatitis herpetiformis**. - While it may take several months to see full skin improvement, it can eventually lead to resolution of skin lesions and reduced or eliminated need for medication. *Dapsone* - **Dapsone** is a rapidly effective medication for alleviating the intense itching and rash of **dermatitis herpetiformis**, often providing relief within 24-48 hours. - It works by inhibiting neutrophil migration and inflammation, but does not treat the underlying gluten-sensitive enteropathy. *Sulfonamide* - **Sulfonamides**, such as sulfapyridine or sulfamethoxypyridazine, can be used as an alternative for patients who cannot tolerate **dapsone** or who respond inadequately to it. - Like dapsone, these medications provide symptomatic relief by reducing inflammation and neutrophil activity in the skin, but do not address the gluten-induced intestinal damage.
Question 1222: What is the most common trigger associated with erythema multiforme?
- A. Herpes simplex (Correct Answer)
- B. Mycoplasma pneumoniae
- C. TB
- D. Drugs
Explanation: ***Herpes simplex*** - **Herpes simplex virus (HSV)** is the most common precipitating factor for **erythema multiforme**, accounting for **50-60% of identifiable cases**, particularly the recurrent form. - The rash typically appears **10-14 days after an HSV outbreak**, suggesting an immune-mediated reaction. - **HSV-1** is more commonly implicated than HSV-2. *Mycoplasma pneumoniae* - **Mycoplasma pneumoniae** is the **second most common infectious trigger** for erythema multiforme, especially in children and young adults. - EM associated with Mycoplasma typically occurs during or after respiratory infection. - However, it is still less common than HSV as a trigger. *TB* - **Tuberculosis (TB)** is not typically associated with erythema multiforme. - While other infections can trigger erythema multiforme, TB is rarely implicated. *Drugs* - **Drug reactions** are a recognized cause of erythema multiforme, but they are less common than HSV infection as a trigger. - Certain medications like **sulfonamides, anticonvulsants, NSAIDs, and penicillins** are among the drugs that can induce erythema multiforme.
Question 1223: Acantholysis is not seen in:
- A. Lichen planus (Correct Answer)
- B. Dermatitis herpetiformis
- C. Hailey-Hailey disease
- D. Bullous pemphigoid
Explanation: ***Lichen planus*** - **Lichen planus** is a **non-blistering inflammatory dermatosis** where **acantholysis is completely absent** as it is not a blistering disorder. - Characterized by **acanthosis** (epidermal thickening), **hyperkeratosis**, **wedge-shaped hypergranulosis**, and a **band-like lymphocytic infiltrate** at the dermo-epidermal junction. - The pathology involves **basal cell liquefaction** and inflammation, not loss of keratinocyte cohesion. - **Most appropriate answer** as lichen planus is fundamentally a non-blistering condition, unlike the other options which are blistering diseases. *Bullous pemphigoid* - A **subepidermal bullous disease** where blister formation occurs *below* the epidermis at the **dermo-epidermal junction**. - Autoantibodies target **BP180 and BP230** antigens in **hemidesmosomes**, causing separation between epidermis and dermis. - **No acantholysis** is present as keratinocytes within the epidermis remain cohesive; the split is subepidermal. - Also a correct answer, but less optimal than lichen planus as it is still a blistering disease. *Dermatitis herpetiformis* - A **subepidermal blistering disease** associated with **celiac disease** and characterized by intensely pruritic papulovesicles. - Features **neutrophilic microabscesses** in dermal papillae and granular **IgA deposits** at the dermo-epidermal junction. - **No acantholysis** as blister formation is subepidermal due to immune complex deposition, not loss of keratinocyte adhesion. - Also technically correct, but lichen planus remains the best answer. *Hailey-Hailey disease* - **INCORRECT:** This condition is characterized by **suprabasal acantholysis**, making it a classic example where acantholysis IS present. - Also known as **familial benign chronic pemphigus**, caused by mutation in **ATP2C1 gene** affecting calcium regulation. - Leads to chronic, relapsing blistering and erosions in **intertriginous areas** (axillae, groin). - **Acantholysis is the defining histological feature**, producing a "dilapidated brick wall" appearance.
Question 1224: Nikolsky's sign is associated with which of the following conditions?
- A. Herpes zoster
- B. Bullous impetigo
- C. All of the options
- D. Pemphigus (Correct Answer)
Explanation: ***Pemphigus*** - **Nikolsky's sign** is the **most characteristic and consistent** clinical finding in pemphigus, where slight lateral pressure on seemingly normal skin near a blister or erosion causes the epidermis to shear off, forming a new blister or denudation. - This sign indicates **intraepidermal blistering** due to the loss of cell adhesion (acantholysis) caused by autoantibodies against desmoglein proteins. - **Pemphigus is the classic condition** associated with a positive Nikolsky's sign in medical literature and examinations. *Herpes zoster* - **Herpes zoster** (shingles) is characterized by painful, vesicular eruptions in a **dermatomal distribution**, which do **not exhibit Nikolsky's sign**. - The vesicles in herpes zoster are **intraepidermal** but result from viral cytopathic effect, not acantholysis, and the roof of the vesicle remains intact with lateral pressure. *Bullous impetigo* - Bullous impetigo is a superficial skin infection caused by *Staphylococcus aureus* that produces **large, flaccid blisters**. - While **Nikolsky's sign can occasionally be positive** in bullous impetigo (particularly in staphylococcal scalded skin syndrome), it is **much less consistent and prominent** compared to pemphigus. - The key distinction is that pemphigus remains the **most characteristic association** with Nikolsky's sign in clinical practice and examinations. *All of the options* - This option is incorrect because Nikolsky's sign is **most specifically and consistently associated with pemphigus**. - While bullous impetigo may occasionally show Nikolsky's sign, **pemphigus is the classic answer** for this clinical finding in medical examinations.
Question 1225: What is the treatment of choice for lichen planus?
- A. Topical corticosteroids (Correct Answer)
- B. Systemic corticosteroids
- C. Antihistamines
- D. Acitretin
Explanation: ***Topical corticosteroids*** - **Topical corticosteroids** are the first-line treatment for localized lichen planus due to their potent **anti-inflammatory** and **immunosuppressive** effects. - They effectively reduce **itching**, **inflammation**, and the characteristic **violaceous papules** of lichen planus. *Systemic corticosteroids* - **Systemic corticosteroids** are typically reserved for widespread, severe, or refractory cases of lichen planus, not as initial treatment. - Their use is limited by potential **systemic side effects**, such as **osteoporosis**, **hypertension**, and **diabetes**. *Antihistamines* - **Antihistamines** primarily target **itching** (pruritus) associated with lichen planus but do not address the underlying **inflammatory process** or resolve the skin lesions themselves. - They may be used as an adjunct for symptomatic relief, especially for nocturnal pruritus. *Acitretin* - **Acitretin** is a **retinoid** used for severe or refractory cases of lichen planus (including erosive, oral, and hypertrophic variants), but not as first-line treatment for localized cutaneous disease. - It carries significant **teratogenic risks** and other side effects, making it unsuitable as initial therapy when topical corticosteroids are effective.
Question 1226: 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 1227: Most common metal in contact allergic dermatitis is?
- A. Gold
- B. Silver
- C. Aluminum
- D. Nickel (Correct Answer)
Explanation: ***Nickel*** - **Nickel** is the most frequent cause of **metal-induced contact allergic dermatitis**, affecting a significant portion of the population. - It is commonly found in jewelry, belt buckles, buttons, and other everyday metallic objects. *Gold* - **Gold allergy** can occur but is much less common than nickel allergy. - Reactions typically arise from jewelry and may involve **allergic contact dermatitis**. *Silver* - **Silver allergy** is quite rare and often due to impurities or alloys rather than pure silver itself. - Pure silver is generally considered **hypoallergenic**. *Aluminum* - **Aluminum** is generally not a common cause of **allergic contact dermatitis**. - While it can be an irritant in some products (e.g., antiperspirants), true allergic reactions are infrequent.
Question 1228: A 25-year-old patient presents with chronic itchy, erythematous skin lesions on the flexural areas that have been recurring since childhood. The patient has a family history of asthma. Which of the following is the most important diagnostic criterion for the most likely diagnosis?
- A. Personal or family history of atopy
- B. Elevated serum IgE levels
- C. Early age of onset (before 2 years)
- D. Chronic pruritic eczema with typical morphology and distribution (Correct Answer)
Explanation: ***Chronic pruritic eczema with typical morphology and distribution*** - The patient presents with **chronic**, **itchy**, **erythematous lesions** on the **flexural areas** (e.g., antecubital and popliteal fossae), characteristic of **atopic dermatitis** (eczema). - The **recurrence since childhood** and the typical distribution represent the **major diagnostic criteria** based on clinical morphology and distribution. - **Clinical presentation with typical morphology** is the **primary diagnostic criterion** according to Hanifin and Rajka criteria. *Elevated serum IgE levels* - While **elevated serum IgE** is often associated with atopic dermatitis, it is a **minor criterion** and a **laboratory finding**, not a primary diagnostic feature. - It reflects an **atopic predisposition**, but **clinical morphology and distribution** remain the most important diagnostic factors. *Personal or family history of atopy* - A **family history of asthma** (an atopic condition) is a **minor criterion** that supports the diagnosis of atopic dermatitis. - However, this is a **predisposing/supporting factor**, not as important as the characteristic clinical morphology and distribution. *Early age of onset (before 2 years)* - While atopic dermatitis often begins in **infancy or early childhood**, this is a **minor criterion** in the diagnostic framework. - The question states symptoms **recurring since childhood** but onset timing is less diagnostically important than the characteristic **clinical presentation** with typical morphology and distribution.
Question 1229: Which of the following conditions does NOT cause nail pitting?
- A. Lichen planus
- B. Fungal infection
- C. Pityriasis Rosea (Correct Answer)
- D. Psoriasis
Explanation: ***Pityriasis Rosea*** - This condition primarily affects the **skin**, causing a distinctive rash of oval, pinkish-red patches, often preceded by a **herald patch**. - It characteristically spares the **nails**, meaning nail pitting is not a feature of pityriasis rosea. - Nail changes are not associated with this self-limiting dermatosis. *Lichen planus* - **Nail lichen planus** can cause various nail changes, including **pitting**, longitudinal ridging, pterygium formation, and thinning of the nail plate. - It is an inflammatory condition affecting the skin, hair, nails, and mucous membranes. - Nail involvement occurs in approximately 10% of patients with cutaneous lichen planus. *Psoriasis* - **Nail psoriasis** is common, affecting up to 50% of patients with psoriasis, and **pitting is the most characteristic nail finding**. - Pitting appears as small punctate depressions on the nail surface due to defects in the proximal nail matrix. - Other nail changes include onycholysis (oil drop sign), subungual hyperkeratosis, and salmon patches. *Fungal infection* - **Onychomycosis** (fungal nail infection) typically causes **thickening, discoloration, onycholysis, and crumbling** of the nail. - **True nail pitting is NOT a characteristic feature** of fungal infections, as pitting results from defects in the proximal nail matrix, not fungal invasion. - Fungal infections affect the nail plate and bed differently, causing destruction rather than the punctate depressions seen in pitting.
Pathology
1 questionsWhat does a Tzanck smear in varicella-zoster virus infection typically show?
NEET-PG 2013 - Pathology NEET-PG Practice Questions and MCQs
Question 1221: What does a Tzanck smear in varicella-zoster virus infection typically show?
- A. Acantholytic cells
- B. Epidermal spongiosis
- C. Multinucleated giant cells (Correct Answer)
- D. Necrotic cells
Explanation: ***Multinucleated giant cells*** - A Tzanck smear identifies **multinucleated giant cells** with intranuclear inclusions, which are characteristic **cytopathic effects** of herpesviruses like VZV [1]. - These cells result from the fusion of infected keratinocytes, a hallmark finding in **herpes simplex** and **varicella-zoster infections** [1]. *Acantholytic cells* - Acantholytic cells are seen in conditions like **pemphigus vulgaris**, where there is loss of cell-to-cell adhesion between keratinocytes, leading to intraepidermal blistering. - While VZV can cause blistering, the primary cytological finding on Tzanck smear is not acantholysis but rather the presence of multinucleated cells. *Epidermal spongiosis* - Spongiosis refers to **intercellular edema** of epidermal cells, leading to widening of the intercellular spaces, typically seen in **eczematous dermatoses** [1]. - This finding is not specific to viral infections and does not represent the characteristic cytopathic effect of VZV on a Tzanck smear. *Necrotic cells* - Necrotic cells, or dead cells, are a general finding in many inflammatory and infectious processes where tissue damage occurs. - While VZV infection can lead to cell necrosis, the presence of isolated necrotic cells is not the specific, diagnostic feature for VZV on a Tzanck smear. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Infectious Diseases, pp. 366-367.