Basic Dermatology Practice Questions

Q: Tzank test is positive in the following conditions, except?

Epstein-Barr Virus (EBV) infection. The **Tzanck smear** is a rapid bedside diagnostic test used primarily to identify **multinucleated giant cells**, which are characteristic of certain viral infections and autoimmune blistering diseases. ### **Why EBV is the Correct Answer** While the **Epstein-Barr Virus (EBV)** belongs to the *Herpesviridae* family, it primarily infects B-lymphocytes and epithelial cells of the oropharynx. It typically presents as Infectious Mononucleosis or Oral Hairy Leukoplakia. Unlike other herpes viruses, EBV does not cause the formation of intraepidermal vesicles or the specific cytopathic changes (like multinucleation and acantholysis) that a Tzanck smear detects. Therefore, the Tzanck test is **negative** in EBV infections. ### **Analysis of Other Options** * **Herpes Simplex (HSV-1 & 2):** Causes "dew drops on rose petals" vesicles. Tzanck smear shows characteristic multinucleated giant cells with **molding, margination of chromatin, and multinucleation** (the 3 M’s). * **Varicella (Chickenpox):** Caused by the Varicella-Zoster Virus (VZV). It produces intraepidermal vesicles where Tzanck cells are abundant. * **Herpes Zoster (Shingles):** Also caused by VZV (reactivation). Like Varicella and HSV, it shows positive Tzanck smears because these viruses are **epidermotropic**. ### **NEET-PG High-Yield Pearls** * **Tzanck Smear Findings:** Look for **multinucleated giant cells** (Tzanck cells). * **Other Positive Conditions:** Apart from HSV/VZV, the Tzanck test is positive in **Pemphigus Vulgaris** (shows acantholytic cells) and **Cytomegalovirus (CMV)** (rarely, but can show "owl’s eye" inclusions). * **Stains Used:** Giemsa, Wright’s, or Leishman stain. * **Limitation:** The Tzanck test can confirm a Herpes group infection but **cannot differentiate** between HSV-1, HSV-2, and VZV. For differentiation, Viral Culture or PCR is required.

Q: A 9-year-old child presents with multiple itchy erythematous wheals all over the body for 2 days, with no respiratory difficulty. What is the most appropriate treatment?

Antihistamines. ### Explanation **Correct Option: C (Antihistamines)** The clinical presentation of itchy, erythematous wheals (hives) without systemic involvement is diagnostic of **Acute Urticaria**. The underlying pathophysiology involves Type I Hypersensitivity, where mast cell degranulation releases histamine, leading to vasodilation and increased capillary permeability. **Second-generation H1-antihistamines** (e.g., Cetirizine, Loratadine) are the first-line treatment as they effectively block H1 receptors, reducing itching and wheal formation with minimal sedation. **Why other options are incorrect:** * **A. Antihelminthics:** While parasitic infections (like *Ascaris*) can cause urticaria, they are not the immediate treatment for an acute symptomatic presentation. They are considered only if the history suggests infestation or if urticaria becomes chronic. * **B. Systemic Corticosteroids:** These are reserved for severe cases, refractory urticaria, or when associated with angioedema. They are not first-line for simple, uncomplicated wheals. * **D. Adrenaline:** This is the life-saving drug of choice for **Anaphylaxis**. Since the patient has no respiratory difficulty (no airway compromise or wheezing) and no hemodynamic instability, adrenaline is not indicated. **Clinical Pearls for NEET-PG:** * **Acute vs. Chronic:** Urticaria is "acute" if it lasts 6 weeks. * **Drug of Choice:** Non-sedating H1 blockers are preferred over first-generation antihistamines (like Pheniramine) due to a better safety profile. * **Anaphylaxis Red Flags:** Always check for "ABC" (Airway, Breathing, Circulation) compromise. If present, the immediate step is **Intramuscular Adrenaline (1:1000)**. * **Common Triggers:** In children, viral infections are the most common cause of acute urticaria, followed by food and medications.

Q: Which of the following is NOT a scrapable white lesion?

Chemical burns. In dermatology and oral pathology, white lesions are clinically categorized based on whether the white patch can be removed by scraping with a tongue depressor or gauze. **Explanation of the Correct Answer:** **C. Chemical Burns:** This is the correct answer because acute chemical burns (e.g., aspirin burn or phenol) result in **coagulative necrosis** of the epithelium. This necrotic tissue forms a pseudomembrane that is loosely attached and **can be easily scraped off**, leaving behind a raw, erythematous, or bleeding base. Therefore, it is a scrapable lesion. **Why the other options are incorrect (Non-scrapable lesions):** * **A. Leukoplakia:** Defined as a clinical term for a white patch that cannot be characterized clinically or pathologically as any other disease. It involves **hyperkeratosis** (thickening of the keratin layer), making it firmly attached and **non-scrapable**. * **B. Lichen Planus:** Specifically the reticular type (Wickham striae), this is an inflammatory condition characterized by hyperkeratosis and a "saw-tooth" appearance of rete ridges. It is **non-scrapable**. * **D. White Sponge Nevus:** A genetic condition (mutation in Keratin 4 or 13) causing thick, bilateral white plaques. Since the pathology involves the entire thickness of the epithelium, it is **non-scrapable**. **NEET-PG High-Yield Pearls:** * **Scrapable White Lesions:** Oral Candidiasis (Thrush) – the most common; Chemical burns; Diphtheritic membrane; Morsicatio buccarum (cheek biting - early stages). * **Non-Scrapable White Lesions:** Leukoplakia; Lichen Planus; White Sponge Nevus; Oral Hairy Leukoplakia (associated with EBV/HIV). * **Clinical Tip:** If a white lesion scrapes off and leaves a bleeding surface, think **Candidiasis**. If it does not scrape off, it requires a biopsy to rule out **dysplasia/malignancy**.

Q: A 37-year-old female presents with multiple, linear, itchy wheals, with itching for 30 minutes at the site. What is the most probable diagnosis?

Dermatographic urticaria. **Explanation:** The clinical presentation of **linear, itchy wheals** appearing shortly after scratching or firm stroking is the hallmark of **Dermatographic Urticaria** (also known as "skin writing" or urticaria factitia). **1. Why Dermatographic Urticaria is correct:** This is the most common form of physical urticaria. It is caused by the release of histamine from mast cells in response to **mechanical shear forces** (like scratching or friction). The wheals typically appear within minutes, are confined to the site of trauma, and resolve within 30–60 minutes. The "linear" pattern mentioned in the question is a classic sign of the patient scratching the skin. **2. Why other options are incorrect:** * **Pressure Urticaria:** This typically presents as deep, painful swelling (rather than itchy linear wheals) that occurs **4–8 hours after** sustained pressure (e.g., from tight waistbands or standing). * **Acute Urticaria:** Defined as hives lasting 6 weeks. Like acute urticaria, these are typically spontaneous and not localized to lines of friction. **Clinical Pearls for NEET-PG:** * **Diagnosis:** Usually clinical; can be confirmed using a **frictest** or a **dermographometer**. * **Treatment:** First-line treatment is **H1 antihistamines** (e.g., Cetirizine, Loratadine). * **Darier’s Sign:** Do not confuse dermatographism with Darier’s sign (wheal and flare formation upon stroking a lesion of **Mastocytosis/Urticaria Pigmentosa**). * **Prevalence:** It affects approximately 2–5% of the general population.

Q: Necrobiosis lipoidica is a clinical finding associated with which of the following conditions?

Diabetes mellitus. **Explanation:** **Necrobiosis Lipoidica (NL)** is a chronic granulomatous skin disorder characterized by the degeneration of dermal collagen (necrobiosis) combined with a granulomatous response, thickening of blood vessel walls, and fat deposition. 1. **Why Diabetes Mellitus is Correct:** NL is most classically associated with **Diabetes Mellitus (DM)**. While only about 0.3–1.2% of diabetic patients develop NL, approximately **60–75% of patients with NL have or will develop diabetes**. The pathogenesis is thought to involve microangiopathy. Clinically, it presents as well-demarcated, erythematous papules that evolve into large, yellow-brown, atrophic, telangiectatic plaques, typically on the **pretibial area (shins)**. 2. **Analysis of Incorrect Options:** * **A. Diabetes Insipidus:** This is a disorder of water metabolism (ADH deficiency or resistance) and has no known association with necrobiotic skin conditions. * **B. Lyme Disease:** Caused by *Borrelia burgdorferi*, it is associated with *Erythema Chronicum Migrans*, not NL. * **D. Symmonds Disease:** Also known as panhypopituitarism, it leads to systemic endocrine deficiencies but does not manifest with NL. **High-Yield Clinical Pearls for NEET-PG:** * **Koebner Phenomenon:** NL can exhibit the Koebner phenomenon (lesions appearing at sites of trauma). * **Ulceration:** About 35% of NL lesions undergo ulceration, often following minor trauma. * **Treatment:** First-line treatment includes high-potency topical or intralesional corticosteroids. * **Distinction:** Unlike other diabetic skin markers (like Acanthosis Nigricans), the severity of NL does **not** correlate with glycemic control.

Q: 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?

Dermatographic urticaria. ### 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.

Q: A 30-year-old woman with type I diabetes, managed with insulin, presents for a dental examination. She reports not having seen a dentist in two years. Intraoral examination reveals a thick, matted appearance on the dorsum of her tongue, leading to a diagnosis of hairy tongue. Which type of papillae is affected, causing this hairlike appearance?

Filiform. **Explanation:** **Hairy Tongue (Lingua Villosa)** is a benign condition characterized by the hypertrophy and elongation of the **filiform papillae** on the dorsal surface of the tongue. 1. **Why Filiform is correct:** Filiform papillae are the most numerous papillae on the tongue. Unlike other types, they are heavily keratinized and do not contain taste buds. In hairy tongue, there is a lack of normal desquamation of the keratin layer, leading to the formation of elongated, hair-like projections (often >15mm). These "hairs" trap debris, bacteria, and fungi, which can lead to discoloration (Black Hairy Tongue). Common triggers include poor oral hygiene, smoking, antibiotics, and systemic conditions like diabetes. 2. **Why other options are incorrect:** * **Foliate:** These are vertical folds located on the lateral margins of the tongue. They contain taste buds but are not involved in the "hairy" presentation. * **Circumvallate:** These are large, circular papillae arranged in a V-shape at the back of the tongue (sulcus terminalis). They contain numerous taste buds and von Ebner’s glands. * **Fungiform:** These are mushroom-shaped, reddish spots scattered mostly at the tip and sides of the tongue. They contain taste buds and do not undergo the keratinization required to produce a "hairy" appearance. **NEET-PG High-Yield Pearls:** * **Filiform papillae** are the only papillae **without taste buds**. * **Black Hairy Tongue** is often associated with *Aspergillus niger* or chromogenic bacteria. * **Geographic Tongue (Benign Migratory Glossitis)** involves the *loss* (atrophy) of filiform papillae, appearing as red patches with white borders. * **Median Rhomboid Glossitis** is a chronic fungal infection (Candidiasis) presenting as a red, depapillated area in the midline of the posterior dorsal tongue.

Q: Oculo-orogenital syndrome is a feature of which of the following conditions?

Behcet's disease. **Explanation:** **Behcet’s Disease** is a chronic, multisystem inflammatory disorder characterized by a relapsing-remitting course of systemic vasculitis. The classic clinical triad, often referred to as the **oculo-orogenital syndrome**, consists of: 1. **Oral ulcers:** Recurrent, painful aphthous-like ulcers (most common initial sign). 2. **Genital ulcers:** Painful ulcers, typically on the scrotum in men or labia in women. 3. **Ocular involvement:** Most commonly **posterior uveitis** or hypopyon, which can lead to blindness if untreated. The underlying pathology is a **leukocytoclastic vasculitis** affecting both small and large vessels. A key diagnostic feature is the **Pathergy test** (development of a papule/pustule 24-48 hours after a sterile needle prick). **Why other options are incorrect:** * **Lichen Planus:** Characterized by the "6 Ps" (Planar, Purple, Polygonal, Pruritic, Papules, and Plaques) and Wickham striae. While it can involve oral and genital mucosa, it lacks the characteristic uveitis/ocular involvement of Behcet’s. * **Systemic Lupus Erythematosus (SLE):** Presents with a malar rash, photosensitivity, and systemic involvement (renal, joint, serositis). While oral ulcers occur, they are typically painless and not part of an oculo-orogenital triad. * **Psoriasis:** Primarily a papulosquamous disorder with silvery scales and the Auspitz sign. Mucosal involvement is rare (except for geographic tongue). **NEET-PG High-Yield Pearls:** * **HLA Association:** Strongly linked with **HLA-B51**. * **Pathergy Test:** Highly specific for Behcet's (also seen in Sweet syndrome and Pyoderma gangrenosum). * **Most common cause of death:** Rupture of large vessel aneurysms (e.g., pulmonary artery). * **Treatment:** Colchicine for mucocutaneous lesions; systemic steroids/immunosuppressants for ocular or systemic disease.

Q: Fox-Fordyce spots represent which of the following?

Apocrine sweat glands. **Explanation:** **Fox-Fordyce disease** (also known as apocrine miliaria) is a chronic inflammatory disorder caused by the **obstruction of the apocrine sweat gland ducts**. The correct answer is **D**. The condition occurs when a keratinous plug blocks the infundibulum of the hair follicle, leading to the rupture of the apocrine duct. This causes sweat to leak into the surrounding dermis, resulting in intense pruritus and the characteristic clinical appearance of multiple, small, firm, skin-colored to yellowish papules. **Analysis of Options:** * **A & B (Pilosebaceous/Sebaceous glands):** While Fox-Fordyce disease involves the hair follicle unit, it specifically affects the apocrine component. Note: **Fordyce spots** (without the "Fox") are ectopic sebaceous glands found on the lips or oral mucosa; these are distinct from Fox-Fordyce disease. * **C (Eccrine sweat glands):** Obstruction of eccrine glands leads to **Miliaria** (rubra, crystallina, or profunda), not Fox-Fordyce disease. **Clinical Pearls for NEET-PG:** * **Demographics:** Predominantly affects young women (ages 13–35). * **Distribution:** Occurs in "apocrine-rich" areas—most commonly the **axilla**, followed by the anogenital region and the areola. * **Key Symptom:** Severe, paroxysmal **itching**, which often worsens with emotional stress or heat (stimuli that trigger apocrine secretion). * **Histopathology:** Characterized by "spongiosis" of the follicular infundibulum and the presence of a keratotic plug. * **Treatment:** First-line treatments include topical retinoids and topical steroids; oral contraceptives may help some patients.

Question 1

Tzank test is positive in the following conditions, except?

Accepted Answer

Epstein-Barr Virus (EBV) infection

Answer

Herpes Zoster

Answer

Herpes Simplex

Answer

Varicella

Question 2

A 9-year-old child presents with multiple itchy erythematous wheals all over the body for 2 days, with no respiratory difficulty. What is the most appropriate treatment?

Accepted Answer

Antihistamines

Answer

Antihelminthics

Answer

Systemic corticosteroids

Answer

Adrenaline

Question 3

Which of the following is NOT a scrapable white lesion?

Accepted Answer

Chemical burns

Answer

Leukoplakia

Answer

Lichen planus

Answer

White sponge nevus

Question 4

A 37-year-old female presents with multiple, linear, itchy wheals, with itching for 30 minutes at the site. What is the most probable diagnosis?

Accepted Answer

Dermatographic urticaria

Answer

Pressure urticaria

Answer

Acute urticaria

Answer

Chronic urticaria

Question 5

Necrobiosis lipoidica is a clinical finding associated with which of the following conditions?

Accepted Answer

Diabetes mellitus

Answer

Diabetes insipidus

Answer

Lyme disease

Answer

Symmonds disease

Question 6

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?

Accepted Answer

Dermatographic urticaria

Answer

Pressure urticaria

Answer

Acute urticaria

Answer

Chronic urticaria

Question 7

A 30-year-old woman with type I diabetes, managed with insulin, presents for a dental examination. She reports not having seen a dentist in two years. Intraoral examination reveals a thick, matted appearance on the dorsum of her tongue, leading to a diagnosis of hairy tongue. Which type of papillae is affected, causing this hairlike appearance?

Accepted Answer

Filiform

Answer

Foliate

Answer

Circumvallate

Answer

Fungiform

Question 8

Oculo-orogenital syndrome is a feature of which of the following conditions?

Accepted Answer

Behcet's disease

Answer

Lichen planus

Answer

Systemic lupus erythematosus (SLE)

Answer

Psoriasis

Question 9

Fox-Fordyce spots represent which of the following?

Accepted Answer

Apocrine sweat glands

Answer

Pilosebaceous glands

Answer

Sebaceous glands

Answer

Eccrine sweat glands

Question 10

Which of the following conditions is NOT transmitted sexually?

Accepted Answer

T. vaginalis

Answer

Syphilis

Answer

Candida

Answer

Gonorrhoea

Basic Dermatology — MCQs

Basic Dermatology — MCQs

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