Dermatitis and Eczema — MCQs

Dermatitis and Eczema Indian Medical PG Practice Questions and MCQs

Question 21: A 19-year-old woman with asthma presents with a chronic, itchy rash distributed on her hands, neck, and elbow creases. Examination reveals thickened skin with increased markings, and fissuring in the elbow creases and hands. What is the most appropriate management advice?

A. Psychoanalysis
B. Wearing warm clothing
C. Maintaining a dry environment
D. Environmental manipulation (Correct Answer)

Explanation: ### **Explanation** **Diagnosis:** The clinical presentation of a young woman with a history of asthma (atopy), chronic pruritus, and skin thickening (lichenification) in flexural areas (elbow creases) and neck is diagnostic of **Atopic Dermatitis (AD)**. **1. Why "Environmental Manipulation" is correct:** Atopic dermatitis is characterized by a defective skin barrier and hypersensitivity to environmental triggers. **Environmental manipulation** is a cornerstone of management to prevent flares. This includes: * Avoiding triggers like harsh soaps, detergents, and allergens (dust mites, pet dander). * Maintaining optimal humidity (avoiding extreme dryness). * Using frequent emollients to restore the skin barrier. * Wearing soft, breathable cotton clothing instead of wool or synthetics. **2. Why the other options are incorrect:** * **A. Psychoanalysis:** While stress can exacerbate AD, it is not a primary treatment. Behavioral therapy (like habit-reversal for scratching) may be used, but psychoanalysis is irrelevant. * **B. Wearing warm clothing:** Heat and sweating are major triggers for itching in AD (sudomotor dysregulation). Patients are advised to stay cool. * **C. Maintaining a dry environment:** Low humidity increases transepidermal water loss (TEWL), worsening the xerosis (dryness) and fissuring characteristic of the disease. **3. NEET-PG High-Yield Pearls:** * **Atopic Triad:** Asthma, Allergic Rhinitis, and Atopic Dermatitis. * **The "Itch that Rashes":** The primary symptom is pruritus; the rash is often a secondary result of scratching. * **Hallmark Sign:** Lichenification (thickened skin with exaggerated markings) due to chronic rubbing. * **Infantile vs. Childhood AD:** Infants typically show involvement of the **face and extensor surfaces**, while older children/adults show **flexural involvement**. * **Filaggrin (FLG) Mutation:** The most common genetic defect associated with skin barrier dysfunction in AD.

Question 22: Which of the following conditions presents with a target or iris lesion?

A. Urticaria
B. Erythema multiforme (Correct Answer)
C. Scabies
D. Lichen planus

Explanation: **Explanation:** **Erythema Multiforme (EM)** is the classic condition characterized by **target or iris lesions**. These are pathognomonic, three-zoned concentric lesions consisting of: 1. A central dusky/purpuric area (sometimes with a vesicle or bulla). 2. A surrounding pale edematous ring. 3. A peripheral erythematous halo. This morphology results from a cell-mediated (Type IV) hypersensitivity reaction, most commonly triggered by **Herpes Simplex Virus (HSV)** or certain drugs. **Analysis of Incorrect Options:** * **Urticaria:** Presents with transient, itchy, erythematous **wheals**. While "annular" urticaria exists, it lacks the three distinct zones of a true target lesion and typically resolves within 24 hours. * **Scabies:** Characterized by intense nocturnal itching and **burrows** (pathognomonic), typically found in web spaces, wrists, and genitalia. * **Lichen Planus:** Presents with the "6 Ps": Planar (flat-topped), Purple, Polygonal, Pruritic, Papules, and Plaques. It is associated with **Wickham striae** (white lacy patterns), not target lesions. **High-Yield Pearls for NEET-PG:** * **Most common trigger for EM Minor:** Herpes Simplex Virus (HSV-1 and HSV-2). * **Most common trigger for EM Major:** Mycoplasma pneumoniae. * **Targetoid vs. True Target:** True target lesions (3 zones) are seen in EM; "Targetoid" lesions (2 zones) can be seen in Stevens-Johnson Syndrome (SJS), though SJS is more characterized by flat, atypical macules and mucosal involvement. * **Histology:** Look for "satellite cell necrosis" (individual keratinocyte necrosis) in the epidermis.

Question 23: In children, atopic dermatitis is associated with an increase in which immunoglobulin?

A. Immunoglobulin A
B. Immunoglobulin E (Correct Answer)
C. Immunoglobulin G
D. Immunoglobulin M

Explanation: ### Explanation **Correct Option: B. Immunoglobulin E (IgE)** Atopic dermatitis (AD) is a chronic, relapsing inflammatory skin disease characterized by a "Type I Hypersensitivity" reaction. The pathogenesis involves a complex interplay between skin barrier dysfunction (often due to **Filaggrin** mutations) and an exaggerated immune response. In children with AD, there is a predominant **Th2 cytokine response** (IL-4, IL-5, and IL-13), which stimulates B-cells to undergo class-switching to produce high levels of **IgE**. Elevated serum IgE is a hallmark of the "Atopic Triad" (Atopic Dermatitis, Asthma, and Allergic Rhinitis). **Why Incorrect Options are Wrong:** * **Option A (IgA):** IgA is primarily involved in mucosal immunity. While selective IgA deficiency is associated with an increased risk of atopy, IgA levels do not typically rise as a primary feature of AD. * **Option C (IgG):** IgG is the most abundant antibody in secondary immune responses and provides long-term immunity against pathogens. It is not the primary mediator of the allergic inflammatory cascade in AD. * **Option D (IgM):** IgM is the first antibody produced in response to an acute primary infection. It does not play a specific role in the chronic allergic inflammation seen in atopic patients. **High-Yield Clinical Pearls for NEET-PG:** * **The Atopic Triad:** AD, Bronchial Asthma, and Allergic Rhinitis. * **Filaggrin (FLG) Gene:** Mutations in this gene on Chromosome 1q21 are the most common genetic risk factor for AD. * **Infantile AD:** Characterized by lesions on the **extensor surfaces** and face (sparing the diaper area). * **Childhood/Adult AD:** Characterized by lesions on the **flexural surfaces** (antecubital and popliteal fossae). * **Dennie-Morgan Fold:** An extra fold of skin under the lower eyelid, a classic clinical sign of atopy. * **Hertoghe’s Sign:** Thinning or loss of the outer third of the eyebrows due to chronic rubbing/itching.

Question 24: Basal cell degeneration is characteristically seen in which of the following conditions?

A. Lichen planus (Correct Answer)
B. Psoriasis
C. Pemphigus
D. Discoid lupus erythematosus (DLE)

Explanation: **Explanation:** The hallmark histopathological feature of **Lichen Planus (LP)** is **Basal Cell Degeneration** (also known as liquefactive necrosis or vacuolar degeneration of the basal layer). This occurs due to a T-cell mediated cytotoxic insult to the basal keratinocytes, leading to the formation of **Civatte bodies** (apoptotic keratinocytes). This process results in the characteristic "saw-tooth" appearance of the rete ridges. **Analysis of Options:** * **Lichen Planus (Correct):** Characterized by the "Interface Dermatitis" pattern, featuring basal cell degeneration, a band-like lymphohistiocytic infiltrate at the dermo-epidermal junction, and hypergranulosis. * **Psoriasis:** The primary features are regular epidermal hyperplasia (psoriasiform), parakeratosis, absent granular layer, and Munro’s microabscesses. The basal layer remains intact. * **Pemphigus:** This is an immunobullous disease characterized by **acantholysis** (loss of intercellular connections) leading to intraepidermal blisters. The basal cells remain attached to the basement membrane, creating a "row of tombstones" appearance. * **Discoid Lupus Erythematosus (DLE):** While DLE *does* show vacuolar degeneration, Lichen Planus is the more "classic" and intense representation of this feature in standard PG examinations. In DLE, this is usually accompanied by follicular plugging and basement membrane thickening. **High-Yield Clinical Pearls for NEET-PG:** * **Wickham Striae:** Reticulate white lines on the surface of LP lesions. * **Koebner Phenomenon:** Seen in LP, Psoriasis, and Vitiligo. * **Max Joseph Spaces:** Small areas of separation between the epidermis and dermis due to extensive basal cell damage in LP. * **Civatte/Colloid Bodies:** PAS-positive apoptotic keratinocytes found in the lower epidermis/upper dermis of LP.

Question 25: A 37-year-old patient presents with multiple wheals at the site of scratch, with itching for 10 minutes. What is the most probable diagnosis?

A. Dermatographic urticaria (Correct Answer)
B. Pressure urticaria
C. Acute urticaria
D. Chronic urticaria

Explanation: ### Explanation **Correct Answer: A. Dermatographic urticaria** **1. Why it is correct:** Dermatographic urticaria (also known as **dermographism** or "skin writing") is the most common form of physical urticaria. It is characterized by the development of a wheal and flare reaction within minutes after the skin is subjected to friction, stroking, or scratching. The underlying mechanism involves the degranulation of mast cells and the release of histamine in response to mechanical shear forces. The rapid onset (within minutes) and the specific trigger (scratching) mentioned in the clinical vignette are classic hallmarks of this condition. **2. Why the other options are incorrect:** * **B. Pressure urticaria:** This typically presents as deep, painful swelling (angioedema) rather than superficial wheals. It occurs 4–6 hours after sustained pressure (e.g., from tight belts or heavy bags), not immediately after a scratch. * **C. Acute urticaria:** Defined as hives lasting less than 6 weeks. While it presents with wheals, it is usually triggered by allergens (food, drugs, or infections) and is generalized rather than localized specifically to the site of a scratch. * **D. Chronic urticaria:** Defined as wheals occurring for more than 6 weeks. It is usually idiopathic and not specifically localized to mechanical trauma like scratching. **3. NEET-PG High-Yield Pearls:** * **Darier’s Sign:** Do not confuse dermographism with Darier’s sign. Darier’s sign is the formation of a wheal after stroking a lesion of **Mastocytosis** (Urticaria Pigmentosa). * **Diagnosis:** Diagnosis is clinical. It can be confirmed using a **dermographometer** or by stroking the skin with a blunt object (like a tongue depressor). * **Treatment:** The mainstay of treatment is **second-generation H1 antihistamines** (e.g., Cetirizine, Loratadine). * **Prevalence:** It affects approximately 2–5% of the general population.

Question 26: Perioral pallor and Dennie's lines are seen in which condition?

A. Atopic dermatitis (Correct Answer)
B. Chronic actinic dermatitis
C. Blood dyscrasias
D. Perioral contact dermatitis

Explanation: **Explanation:** The correct answer is **Atopic Dermatitis (AD)**. This condition is a chronic, relapsing inflammatory skin disease characterized by intense pruritus and a specific distribution of lesions. Diagnosis is primarily clinical, based on the **Hanifin and Rajka criteria**, which include several "minor" clinical signs. * **Dennie-Morgan Lines:** These are characteristic infraorbital folds or wrinkles caused by chronic edema and inflammation of the lower eyelids. * **Perioral Pallor:** This refers to a pale appearance around the mouth, often contrasting with the erythematous, eczematous patches on the cheeks (common in the infantile phase). **Analysis of Incorrect Options:** * **Chronic actinic dermatitis:** An immunologically mediated photosensitivity disorder. It presents as eczematous lesions in sun-exposed areas, not typically associated with these specific infraorbital or perioral signs. * **Blood dyscrasias:** These usually present with purpura, petechiae, or mucosal bleeding rather than eczematous features or Dennie-Morgan lines. * **Perioral contact dermatitis:** While it involves the perioral area, it typically presents with erythema, scaling, and papules *around* the mouth, often sparing a thin rim of skin near the vermilion border. It does not feature Dennie-Morgan lines. **High-Yield Clinical Pearls for NEET-PG:** * **Hertoghe’s sign:** Thinning or loss of the lateral third of the eyebrows (seen in AD and Hypothyroidism). * **Pityriasis alba:** Hypopigmented, slightly scaly patches on the face; a minor criterion for AD. * **Hyperlinear palms:** Increased skin markings on the palms, frequently associated with Ichthyosis vulgaris and AD. * **Dermatographism:** Patients with AD often show **white dermatographism** (vasoconstriction) instead of the typical red wheal.

Question 27: Sago grain-like vesicular eruption is characteristic of which condition?

A. Pompholyx (Correct Answer)
B. Seborrhoeic dermatitis
C. Atopic dermatitis
D. Syphilis

Explanation: **Explanation:** **1. Why Pompholyx is correct:** Pompholyx, also known as **Dysidrotic Eczema**, is a specific type of vesicular palmoplantar dermatitis. The hallmark clinical feature is the sudden onset of deep-seated, firm, pruritic vesicles on the lateral aspects of the fingers, palms, and soles. Because these vesicles are located beneath the thick stratum corneum of the palms and soles, they do not rupture easily and instead resemble **"sago grains"** (small, translucent, pearl-like bumps). **2. Why the other options are incorrect:** * **Seborrhoeic dermatitis:** Characterized by erythematous plaques with **greasy, yellowish scales** in areas with high sebaceous gland density (scalp, nasolabial folds, chest). It does not present with deep-seated vesicles. * **Atopic dermatitis:** Typically presents as ill-defined erythematous, itchy patches with lichenification in flexural areas (popliteal and antecubital fossae). While it can coexist with pompholyx, "sago grain" vesicles are not its primary morphology. * **Syphilis:** Secondary syphilis commonly involves the palms and soles, but the lesions are typically **copper-colored maculopapules** or "raw ham" colored lesions, often associated with generalized lymphadenopathy and a polymorphic rash. **3. Clinical Pearls for NEET-PG:** * **Triggers:** Emotional stress, heat, and nickel/cobalt sensitivity are common exacerbating factors. * **Cheiropompholyx:** Term used when only the hands are involved. * **Podopompholyx:** Term used when only the feet are involved. * **Management:** High-potency topical corticosteroids are the first-line treatment. * **Differential Diagnosis:** Must be differentiated from Bullous Tinea Pedis (perform a KOH mount) and Pustular Psoriasis.

Question 28: Dennie Morgan fold is seen in?

A. Mastocytosis
B. Seborrhoic dermatitis
C. Sarcoidosis
D. Atopic dermatitis (Correct Answer)

Explanation: **Explanation:** **Dennie-Morgan fold** (also known as Dennie-Morgan line or infraorbital fold) is a characteristic clinical sign of **Atopic Dermatitis (AD)**. It refers to a single or double horizontal fold or groove beneath the lower eyelid caused by chronic inflammation and edema of the eyelid skin. 1. **Why Atopic Dermatitis is correct:** AD is a chronic inflammatory skin condition associated with a defective skin barrier (often due to Filaggrin mutations). The Dennie-Morgan fold is one of the **minor criteria** in the Hanifin and Rajka diagnostic system for AD. It results from persistent rubbing of the eyes and chronic dermatitis in the periorbital region, leading to skin hypertrophy and accentuated creases. 2. **Why other options are incorrect:** * **Mastocytosis:** Characterized by mast cell infiltration. Key signs include the **Darier sign** (wheal formation upon stroking a lesion). * **Seborrheic Dermatitis:** Typically presents with greasy, yellowish scales on erythematous bases in "seborrheic areas" (scalp, nasolabial folds, chest), but does not feature infraorbital folds. * **Sarcoidosis:** A multisystem granulomatous disease. Cutaneous findings include **Lupus Pernio** or erythema nodosum, not specific infraorbital creasing. **High-Yield Clinical Pearls for NEET-PG:** * **Atopic Stigmata:** Other high-yield signs of AD include **Hertoghe’s sign** (thinning of the lateral third of eyebrows), **Pityriasis alba** (hypopigmented patches on the face), and **Hyperlinear palms**. * **The Atopic March:** The typical progression from Atopic Dermatitis → Food Allergy → Allergic Rhinitis → Asthma. * **Associated Conditions:** AD is frequently associated with **Ichthyosis vulgaris** and keratosis pilaris.

Question 29: What condition is characterized by "white dermographism"?

A. Atopic dermatitis (Correct Answer)
B. Airborne contact dermatitis
C. Chemical dermatitis
D. Seborrheic dermatitis

Explanation: **Explanation:** **White Dermographism** is a pathognomonic clinical sign of **Atopic Dermatitis (AD)**. In a healthy individual, stroking the skin firmly results in a "triple response of Lewis" (red line, flare, and wheal) due to capillary dilatation and exudation. However, in patients with Atopic Dermatitis, firm stroking results in a **white line** appearing within seconds, replacing the initial red line. This occurs due to **abnormal capillary vasoconstriction** in response to pressure, a result of altered autonomic vascular reactivity and increased sensitivity to catecholamines in atopic skin. **Analysis of Incorrect Options:** * **B. Airborne Contact Dermatitis:** This is a type IV hypersensitivity reaction to aeroallergens (like *Parthenium*). It typically presents with "sun-exposed" distribution (face, V-area of neck) and does not exhibit white dermographism. * **C. Chemical Dermatitis:** Whether irritant or allergic, these are localized inflammatory responses to specific triggers. The underlying pathophysiology involves direct cellular damage or delayed hypersensitivity, not the generalized autonomic vasomotor instability seen in AD. * **D. Seborrheic Dermatitis:** This is a chronic inflammatory condition related to *Malassezia* yeast in sebum-rich areas (scalp, nasolabial folds). It lacks the systemic vasomotor dysfunction characteristic of the atopic state. **NEET-PG High-Yield Pearls:** * **Hertoghe’s sign:** Thinning of the lateral one-third of eyebrows (seen in AD and Hypothyroidism). * **Dennie-Morgan fold:** An extra fold of skin under the lower eyelid in AD. * **Darier’s Sign:** Seen in Mastocytosis (stroking leads to a wheal/urtication), which is the opposite of white dermographism. * **Atopic Triad:** Asthma, Allergic Rhinitis, and Atopic Dermatitis.

Question 30: Which of the following is the most common cause of metal allergy due to jewellery?

A. Silver
B. Gold
C. Iron
D. Nickel (Correct Answer)

Explanation: **Explanation:** **1. Why Nickel is the Correct Answer:** Nickel is the most common cause of **Allergic Contact Dermatitis (ACD)** worldwide. It is a potent sensitizer and is ubiquitous in inexpensive jewelry, watch straps, belt buckles, and zippers. The underlying mechanism is a **Type IV (Delayed-type) Hypersensitivity reaction**, mediated by T-cells. When sweat comes into contact with jewelry, it leaches nickel ions, which then act as haptens, binding to skin proteins to trigger an immune response. **2. Why the Other Options are Incorrect:** * **Silver (A):** Pure silver is rarely allergenic. Most "silver" allergies are actually reactions to nickel used as a base metal or alloy in sterling silver. * **Gold (B):** While gold (specifically gold sodium thiosulfate) is a known allergen, it is significantly less common than nickel. Like silver, reactions to gold jewelry are often due to nickel contamination or alloys. * **Iron (C):** Iron is not a common skin sensitizer and does not typically cause allergic contact dermatitis. **3. Clinical Pearls for NEET-PG:** * **Dimethylglyoxime Test:** A high-yield bedside test used to detect the presence of nickel in metallic objects (turns pink in the presence of nickel). * **Clinical Presentation:** Often presents as "earring dermatitis" or "infra-umbilical dermatitis" (due to jean buttons/belt buckles). * **Patch Testing:** This is the **Gold Standard** investigation for diagnosing the specific allergen in Allergic Contact Dermatitis. * **Cross-reactivity:** Patients allergic to nickel may also show sensitivity to **Cobalt** and **Chromium**.

Practice by Chapter

Atopic Dermatitis

Practice Questions

Seborrheic Dermatitis

Practice Questions

Contact Dermatitis: Irritant

Practice Questions

Contact Dermatitis: Allergic

Practice Questions

Nummular Eczema

Practice Questions

Dyshidrotic Eczema

Practice Questions

Stasis Dermatitis

Practice Questions

Asteatotic Eczema

Practice Questions

Lichen Simplex Chronicus

Practice Questions

Autoeczematization (Id Reaction)

Practice Questions

Photosensitive Eczemas

Practice Questions

Treatment Strategies for Eczematous Disorders

Practice Questions

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