NEET-PG 2013 - Dermatology Practice Questions

Q: Most common metal in contact allergic dermatitis is?

Nickel. ***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.

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

Psoriasis. ***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

Q: What is the treatment of choice for lichen planus?

Topical corticosteroids. ***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.

Q: Nikolsky's sign is associated with which of the following conditions?

Pemphigus. ***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.

Q: What does a Tzanck smear in varicella-zoster virus infection typically show?

Multinucleated giant cells. ***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.

Q: What is the most common trigger associated with erythema multiforme?

Herpes simplex. ***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.

Q: Treatment of dermatitis herpetiformis:

All of the options. ***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.

Q: A man with pain during defecation, no gastrointestinal symptoms, and ulcers extending into the anal canal. Diagnosis?

Genital herpes. Herpes simplex virus (HSV) infection of the anal canal is characterized by lesions that present as painful ulcers [1]. Direct extension into the anal canal is common in individuals with receptive anal intercourse or autoinoculation, often causing symptoms such as anal or rectal pain [1]. CMV proctitis typically causes more diffuse inflammation, often with bloody stools, diarrhea, and abdominal pain, which are not described in this case. While CMV can cause ulcers, they are usually shallow and often associated with immunocompromised states. Gonococcal proctitis often presents with purulent anal discharge, rectal pain, itching, and tenesmus, but typically without deep ulcerations. HIV infection can cause various anorectal complications, including aphthous ulcers, but isolated anal ulcers and defecation pain would prompt investigation into sexually transmitted infections like herpes as a more direct cause.

Q: In which condition is an ulceronecrotic nodule typically observed?

Lucio's leprosy. ***Lucio's leprosy*** - This is a rare, diffuse variant of **lepromatous leprosy** characterized by widespread, diffuse infiltration of the skin without distinct nodules. - The distinctive feature is the occurrence of **necrotizing vasculitis**, leading to painful, irregular ulcers and scars, known as **Lucio phenomenon** or erythema necroticans. *Lepromatous leprosy* - Characterized by **multiple, symmetrical nodules**, plaques, and diffuse infiltration, but typically without the profound ulceronecrotic changes seen in Lucio's leprosy. - The immune response is weak, leading to high bacterial load and widespread involvement, but usually not spontaneous ulceration. *Indeterminate leprosy* - This is an **early, undifferentiated form** of leprosy, characterized by a single or a few hypopigmented or erythematous macules. - Distinct nodules or ulceronecrotic lesions are not a feature of indeterminate leprosy, as the disease has not yet progressed to develop specific clinical manifestations. *Histoid leprosy* - A rare variant of lepromatous leprosy that presents with **cutaneous nodules** and papules that often resemble dermatofibromas or xanthomas. - These nodules are firm, smooth, and have a unique histological appearance, but they do not typically undergo spontaneous ulceronecrotic changes like those in Lucio's leprosy.

Question 1

Most common metal in contact allergic dermatitis is?

Accepted Answer

Nickel

Answer

Gold

Answer

Silver

Answer

Aluminum

Question 2

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

Accepted Answer

Psoriasis

Answer

Tinea capitis

Answer

Lichen planus

Answer

Pemphigus vulgaris

Question 3

What is the treatment of choice for lichen planus?

Accepted Answer

Topical corticosteroids

Answer

Systemic corticosteroids

Answer

Antihistamines

Answer

Acitretin

Question 4

Nikolsky's sign is associated with which of the following conditions?

Accepted Answer

Pemphigus

Answer

Herpes zoster

Answer

Bullous impetigo

Answer

All of the options

Question 5

What does a Tzanck smear in varicella-zoster virus infection typically show?

Accepted Answer

Multinucleated giant cells

Answer

Acantholytic cells

Answer

Epidermal spongiosis

Answer

Necrotic cells

Question 6

Acantholysis is not seen in:

Accepted Answer

Lichen planus

Answer

Dermatitis herpetiformis

Answer

Hailey-Hailey disease

Answer

Bullous pemphigoid

Question 7

What is the most common trigger associated with erythema multiforme?

Accepted Answer

Herpes simplex

Answer

Mycoplasma pneumoniae

Answer

TB

Answer

Drugs

Question 8

Treatment of dermatitis herpetiformis:

Accepted Answer

All of the options

Answer

Dapsone

Answer

Sulfonamide

Answer

Gluten-free diet

Question 9

A man with pain during defecation, no gastrointestinal symptoms, and ulcers extending into the anal canal. Diagnosis?

Accepted Answer

Genital herpes

Answer

Cytomegalovirus (CMV)

Answer

Gonococcal infection

Answer

HIV infection

Question 10

In which condition is an ulceronecrotic nodule typically observed?

Accepted Answer

Lucio's leprosy

Answer

Lepromatous leprosy

Answer

Indeterminate leprosy

Answer

Histoid leprosy

NEET-PG 2013 — Dermatology