NEET-PG 2013 - Dermatology Practice Questions

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 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: 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.

Q: Skin scraping and KOH mounting is primarily used to diagnose which of the following conditions?

Dermatophyte infection. ***Dermatophyte infection*** - Skin scraping followed by **KOH mounting** is the **primary and gold standard** diagnostic method for dermatophyte infections - **Potassium hydroxide (KOH)** dissolves keratin, making **fungal hyphae and arthroconidia** clearly visible under microscopy - This is the **most common indication** for KOH preparation in dermatology practice - Demonstrates **septate hyphae** characteristic of dermatophytes *Candidiasis* - KOH mounting can also identify *Candida* species by revealing **pseudohyphae and budding yeast cells** - While KOH can diagnose candidiasis, dermatophyte infections remain the **primary and most frequent indication** for this test in skin lesions - Candida more commonly affects mucosal surfaces where other diagnostic methods may be preferred *Bacterial infection* - Bacterial infections are diagnosed using **Gram stain, culture, and sensitivity** testing - KOH mounting is specifically for **fungal elements** and does not visualize bacteria effectively - Bacterial skin infections require different diagnostic approaches *Herpes Simplex Virus (HSV)* - HSV infections are diagnosed using **Tzanck smear** (showing multinucleated giant cells), **viral culture, or PCR** - KOH mounting is exclusively for fungal identification and **cannot detect viruses** - Viral cytopathic effects are not visible with KOH preparation

Q: Which of the following drugs is effective in the treatment of pityriasis versicolor?

Ketoconazole. ***Ketoconazole*** - **Ketoconazole** is an **azoles antifungal agent** effective against the *Malassezia* species, the causative agent of **pityriasis versicolor**. - It works by inhibiting the synthesis of **ergosterol**, a crucial component of the fungal cell membrane, leading to its disruption and fungal cell death. *Metronidazole* - **Metronidazole** is an **antibiotic** and **amoebicide** primarily used to treat bacterial and parasitic infections. - It has **no antifungal activity** and is thus ineffective against *Malassezia* or other fungal infections. *Griseofulvin* - **Griseofulvin** is an **oral antifungal drug** primarily used for **dermatophyte infections** of the skin, hair, and nails (e.g., tinea capitis, onychomycosis). - It is **ineffective against yeasts and molds**, including *Malassezia*, making it unsuitable for pityriasis versicolor. *Chloroquine* - **Chloroquine** is an **antimalarial drug** also used in the treatment of some autoimmune conditions like lupus erythematosus. - It possesses **no antifungal properties** and is not used to treat fungal infections of any kind.

Q: Pathergy test is used for which condition?

Behçet's syndrome. ***Behçet's syndrome*** - The **pathergy test** is a diagnostic test where a sterile needle is used to prick the skin, and a positive result (erythematous papule or pustule) indicates a hyperreactivity of the skin, common in **Behçet's syndrome**. - This syndrome is a **vasculitis** characterized by recurrent oral and genital ulcers, ocular inflammation, and skin lesions, where pathergy is a characteristic feature. *Lichen planus* - This is an **inflammatory dermatosis** affecting the skin, hair, nails, and mucous membranes, characterized by "6 P's": **Pruritic, Purple, Polygonal, Planar, Papules, and Plaques**. - The pathergy test is **not used** in the diagnosis of lichen planus. *Atopic dermatitis* - Also known as **eczema**, it is a chronic, relapsing inflammatory skin condition characterized by dry, itchy skin and often associated with a personal or family history of allergies, asthma, or allergic rhinitis. - Diagnosis is primarily clinical, focusing on characteristic skin lesions and symptoms, and the **pathergy test is not applicable**. *Reiter's syndrome* - Now known as **reactive arthritis**, this condition is an autoimmune disorder that develops in response to an infection elsewhere in the body, typically genitourinary or gastrointestinal. - It classically presents with **arthritis, urethritis, and conjunctivitis** (Can't see, can't pee, can't climb a tree), and the **pathergy test is not used** for its diagnosis.

Q: What percentage of skin involvement is characteristic of erythroderma?

More than 90%. ***More than 90%*** - Erythroderma, also known as **exfoliative dermatitis**, is defined by diffuse redness and scaling involving **more than 90% of the body surface area**. - This extensive involvement leads to significant physiological disturbances due to impaired skin barrier function. *Less than 30%* - Skin involvement less than 30% does not meet the criteria for erythroderma and would be considered more localized dermatological conditions. - This percentage of involvement would typically indicate a benign rash or localized eczema, not a widespread inflammatory process. *30% to 60%* - While significant, 30% to 60% skin involvement is still insufficient to classify a condition as erythroderma. - This range might be seen in severe but still localized forms of conditions like psoriasis or eczema. *60% to 70%* - 60% to 70% involvement is extensive but falls short of the critical threshold for erythroderma. - Although indicating widespread disease, it does not constitute the near-total body erythema and scaling characteristic of erythroderma.

Q: What is the treatment for granuloma inguinale?

Azithromycin. ***Azithromycin*** - **Azithromycin** is the recommended first-line treatment for **granuloma inguinale** (donovanosis) caused by *Klebsiella granulomatis*. - Current recommended regimens: **Azithromycin 1g orally once weekly** OR **500mg daily for at least 3 weeks** (until all lesions have completely healed). - Preferred due to excellent tissue penetration, good efficacy, and convenient dosing that improves patient compliance. *Tetracycline* - **Tetracycline** (500mg four times daily) was historically used but has been largely replaced by **doxycycline** (100mg twice daily) as the preferred tetracycline-class antibiotic. - While effective against *Klebsiella granulomatis*, it requires frequent dosing leading to poor adherence. - **Doxycycline** (not listed here) is actually considered a co-first-line option alongside azithromycin in current CDC guidelines. *Clarithromycin* - **Clarithromycin** is a macrolide antibiotic but is not a recommended first-line agent for granuloma inguinale. - Limited clinical data supports its use for this condition, and it is not included in standard treatment guidelines. - Azithromycin from the same macrolide class is preferred due to better-established efficacy. *Streptomycin* - **Streptomycin** is an aminoglycoside antibiotic primarily used for mycobacterial infections (e.g., tuberculosis, plague). - Not indicated for granuloma inguinale as *Klebsiella granulomatis* responds well to macrolides (azithromycin) and tetracyclines (doxycycline). - Requires parenteral administration and has significant toxicity concerns (ototoxicity, nephrotoxicity).

Question 1

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 2

Acantholysis is not seen in:

Accepted Answer

Lichen planus

Answer

Dermatitis herpetiformis

Answer

Hailey-Hailey disease

Answer

Bullous pemphigoid

Question 3

What is the most common trigger associated with erythema multiforme?

Accepted Answer

Herpes simplex

Answer

Mycoplasma pneumoniae

Answer

TB

Answer

Drugs

Question 4

Treatment of dermatitis herpetiformis:

Accepted Answer

All of the options

Answer

Dapsone

Answer

Sulfonamide

Answer

Gluten-free diet

Question 5

In which condition is an ulceronecrotic nodule typically observed?

Accepted Answer

Lucio's leprosy

Answer

Lepromatous leprosy

Answer

Indeterminate leprosy

Answer

Histoid leprosy

Question 6

Skin scraping and KOH mounting is primarily used to diagnose which of the following conditions?

Accepted Answer

Dermatophyte infection

Answer

Bacterial infection

Answer

Candidiasis

Answer

Herpes Simplex Virus (HSV)

Question 7

Which of the following drugs is effective in the treatment of pityriasis versicolor?

Accepted Answer

Ketoconazole

Answer

Metronidazole

Answer

Griseofulvin

Answer

Chloroquine

Question 8

Pathergy test is used for which condition?

Accepted Answer

Behçet's syndrome

Answer

Lichen planus

Answer

Atopic dermatitis

Answer

Reiter's syndrome

Question 9

What percentage of skin involvement is characteristic of erythroderma?

Accepted Answer

More than 90%

Answer

Less than 30%

Answer

30% to 60%

Answer

60% to 70%

Question 10

What is the treatment for granuloma inguinale?

Accepted Answer

Azithromycin

Answer

Tetracycline

Answer

Clarithromycin

Answer

Streptomycin

NEET-PG 2013 — Dermatology