NEET-PG 2013 — Dermatology
31 Previous Year Questions with Answers & Explanations
Tinea cruris is caused by which of the following fungi?
Which of the following statements is true about rhinophyma?
What is the condition characterized by the hypertrophy of sebaceous glands?
Lines of Blaschko are related to?
Which of the following causes non-cicatricial alopecia?
Which of the following conditions does NOT cause nail pitting?
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?
The Grattage test is used to diagnose which of the following conditions?
Most common metal in contact allergic dermatitis is?
What is the treatment of choice for lichen planus?
NEET-PG 2013 - Dermatology NEET-PG Practice Questions and MCQs
Question 1: Tinea cruris is caused by which of the following fungi?
- A. Epidermophyton (Correct Answer)
- B. Trichosporon
- C. Microsporum
- D. Candida
Explanation: ***Epidermophyton*** - **_Epidermophyton floccosum_** is one of the common dermatophytes responsible for causing **tinea cruris** (jock itch) and tinea pedis (athlete's foot). - **Note:** Tinea cruris can be caused by multiple dermatophytes including **_Trichophyton rubrum_** (most common), **_T. mentagrophytes_**, and **_E. floccosum_**. Among the options listed, Epidermophyton is the only dermatophyte that commonly causes tinea cruris. - Microscopic examination of skin scrapings shows **septate hyphae**, and it typically invades the stratum corneum but **not hair or nails**. *Trichosporon* - **_Trichosporon_** species cause **white piedra** (a fungal infection of the hair shaft) and can cause systemic infections in immunocompromised individuals. - It is **not a dermatophyte** and does not cause tinea cruris. *Microsporum* - **_Microsporum_** species are primarily associated with **tinea capitis** (ringworm of the scalp) and **tinea corporis** (ringworm of the body). - While Microsporum can occasionally involve skin in the groin region, it is **rarely implicated in classic tinea cruris** and is not considered a typical causative agent compared to Trichophyton or Epidermophyton species. *Candida* - **_Candida_** species (e.g., **_Candida albicans_**) cause candidiasis, which commonly presents as **intertrigo** in skin folds, oral thrush, or vaginal yeast infections. - While it can occur in the groin area (**candidal intertrigo**), it is **not a dermatophyte** and is distinctly different from tinea cruris, often presenting with **satellite lesions** and an intensely erythematous, macerated rash.
Question 2: Which of the following statements is true about rhinophyma?
- A. Premalignant
- B. Common in alcoholics
- C. Acne rosacea (Correct Answer)
- D. Fungal etiology
Explanation: ***Acne rosacea*** - **Rhinophyma** is a severe form of **acne rosacea**, characterized by sebaceous gland hypertrophy and connective tissue hyperplasia on the nose. - It specifically represents the **phymatous subtype** of rosacea, which involves thickening of the skin. *Premalignant* - Rhinophyma itself is generally **not considered premalignant** to skin cancer. - While skin cancers like **basal cell carcinoma** can rarely occur within rhinophyma, the condition itself does not inherently transform into malignancy. *Common in alcoholics* - This is a **common misconception**; while often associated with heavy alcohol use, there is no direct causal link. - The development of rhinophyma is primarily driven by the underlying pathogenesis of **rosacea**, not alcohol consumption. *Fungal etiology* - Rhinophyma is primarily an inflammatory skin condition, not caused by **fungal infection**. - Its etiology is complex, involving genetics, environmental triggers, and vascular dysregulation, but **microbial involvement** is typically bacterial (e.g., Demodex mites) rather than fungal.
Question 3: What is the condition characterized by the hypertrophy of sebaceous glands?
- A. Rhinosporidiosis
- B. Tubercular infection
- C. Sebaceous hyperplasia (Correct Answer)
- D. Nasopharyngeal angiofibroma
Explanation: ***Sebaceous hyperplasia*** - This condition is characterized by the **enlargement (hypertrophy)** of normal sebaceous glands, often appearing as yellowish-white papules with a central umbilication. - It commonly occurs on the **face of older adults**, particularly on the forehead and cheeks, and is a benign condition. *Rhinosporidiosis* - This is a **chronic granulomatous disease** caused by the fungus *Rhinosporidium seeberi*, primarily affecting the **mucous membranes** of the nose and nasopharynx. - It presents as **friable, polypoidal masses** with a characteristic "strawberry-like" appearance due to small white spots (sporangia), not sebaceous gland hypertrophy. *Tubercular infection* - A tubercular infection, particularly cutaneous tuberculosis, can manifest in various forms, including **lupus vulgaris**, scrofuloderma, or tuberculosis cutis verrucosa. - These presentations involve **granulomatous inflammation** and tissue destruction, not isolated hypertrophy of sebaceous glands. *Nasopharyngeal angiofibroma* - This is a **rare, benign, highly vascular tumor** that originates in the nasopharynx, predominantly affecting adolescent males. - It typically presents with symptoms like **epistaxis** and **nasal obstruction**, and is composed of fibrous and vascular tissue, not sebaceous glands.
Question 4: Lines of Blaschko are related to?
- A. Keratinocytes (Correct Answer)
- B. Blood vessels
- C. Nerves
- D. Bones
Explanation: ***Keratinocytes*** - **Lines of Blaschko** represent the migratory pathways of embryonic cells, primarily **keratinocytes**, in the skin. - These lines are not visible under normal conditions but become apparent in various **genetic skin disorders** where abnormal cells follow these specific patterns. *Blood vessels* - While blood vessels are extensively present in the skin, they do not follow the specific **migratory patterns** described by the Lines of Blaschko. - Their arrangement is more related to **vascular networks** and anatomical supply rather than embryonic cell migration. *Nerves* - **Nerves** in the skin have specific distributions, often following dermatomal patterns, which are distinct from the **Lines of Blaschko**. - Nerve distribution is related to their segmental origin from the **spinal cord**, not the migratory paths of epidermal cells. *Bones* - **Bones** are part of the skeletal system and are not found in the skin, making them unrelated to the **Lines of Blaschko**. - These lines describe epidermal cell migration, which is a feature of the **integumentary system**.
Question 5: Which of the following causes non-cicatricial alopecia?
- A. Tinea capitis
- B. SLE
- C. Alopecia areata
- D. All of the options (Correct Answer)
Explanation: ***All of the options*** - **Tinea capitis**, **SLE** (Systemic Lupus Erythematosus), and **Alopecia areata** all can cause **non-cicatricial alopecia**. - **Non-cicatricial alopecia** refers to hair loss where the hair follicle is not permanently destroyed, and hair regrowth is possible, leaving no scarring. *Tinea capitis* - This is a **fungal infection** of the scalp that causes hair shafts to break, leading to patches of hair loss. - While it can lead to inflammation, it typically does not cause permanent destruction of the hair follicle unless severe and untreated, thus being predominantly **non-cicatricial**. *SLE* - Hair loss in **SLE** can occur due to various mechanisms, including diffuse thinning, patchy alopecia, or the characteristic "**lupus hair**" (fragile hairs around the hairline). - This type of hair loss is usually **non-scarring** and reversible, although discoid lupus erythematosus often causes scarring alopecia. *Alopecia areata* - This is an **autoimmune condition** characterized by patchy, sudden hair loss on the scalp or other body parts. - The hair follicles are attacked by the immune system but are not destroyed, making the condition largely **non-cicatricial** and potentially reversible.
Question 6: 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.
Question 7: 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 8: 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 9: 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 10: 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.