NEET-PG 2012 — Dermatology
19 Previous Year Questions with Answers & Explanations
Which of the following statements is true regarding donovanosis?
Raindrop pigmentation is caused by?
Loss of intercellular cohesion between keratinocytes is referred to as?
Which of the following is NOT a feature of atopic dermatitis?
Which of the following skin lesions is not classified as a nevus of melanocytes?
Which of the following is NOT a characteristic of dermatophytosis?
Which of the following is the MOST characteristic feature of skin tags (acrochordons)?
Which of the following statements about spider telangiectasia is false?
In which of the following conditions is the Koebner phenomenon most commonly observed?
Which of the following is not a feature of dermatomyositis?
NEET-PG 2012 - Dermatology NEET-PG Practice Questions and MCQs
Question 1: Which of the following statements is true regarding donovanosis?
- A. Pseudolymphadenopathy is characteristic
- B. Penicillin is used for treatment
- C. Painful ulcer is characteristic
- D. Painless ulcerative lesions are characteristic of donovanosis (Correct Answer)
Explanation: ***Painless ulcerative lesions are characteristic of donovanosis*** - Donovanosis, also known as granuloma inguinale, is characterized by **painless, progressive ulcerative lesions** that can bleed easily. - The lesions typically start as papules or nodules and then erode to form **granulomatous ulcers** with a beefy red appearance. - This is a key distinguishing feature from chancroid (painful ulcers) and primary syphilis. *Pseudolymphadenopathy is characteristic* - While donovanosis can lead to swelling in the inguinal region, it's typically **pseudobuboes** (subcutaneous granulomas) rather than true lymphadenopathy. - However, this is not a defining characteristic, as pseudobuboes are less common and occur in advanced cases. - The primary feature remains the **painless ulcerative lesions**. *Penicillin is used for treatment* - **Penicillin** is not the standard treatment for donovanosis; it is ineffective against *Klebsiella granulomatis*. - The recommended treatment involves **macrolides** (e.g., azithromycin) or **tetracyclines** (e.g., doxycycline) for at least 3 weeks or until lesions heal. - Alternative regimens include **cotrimoxazole** or **fluoroquinolones**. *Painful ulcer is characteristic* - Donovanosis ulcers are typically **painless**, which distinguishes them from other genital ulcers like those seen in herpes or chancroid. - The **lack of pain** often contributes to delayed presentation and progression of the disease.
Question 2: Raindrop pigmentation is caused by?
- A. Dapsone
- B. Minocycline
- C. Clofazimine
- D. Arsenic (Correct Answer)
Explanation: ***Arsenic*** - Chronic **arsenic** exposure can lead to characteristic skin manifestations, including **raindrop pigmentation**, which appears as small, scattered hypopigmented macules surrounded by hyperpigmented skin, particularly on the trunk and extremities. - This pigmentation is a result of altered **melanin distribution** and **keratinocyte damage** due to arsenic toxicity. *Clofazimine* - **Clofazimine** is an anti-leprosy drug that can cause **reddish-brown to bluish-black skin discoloration**, which is a diffuse pigmentation, not "raindrop" in nature. - The pigmentation associated with clofazimine is due to drug deposition in tissues and is usually reversible. *Dapsone* - **Dapsone** is primarily known for causing **methemoglobinemia** and **hemolytic anemia**, especially in patients with G6PD deficiency. - While it can cause some dermatological side effects, **pigmentation** is not a characteristic feature, and it does not produce a "raindrop" pattern. *Minocycline* - **Minocycline** can cause various types of pigmentation, including **blue-gray discoloration** in scars, shins, and mucous membranes, as well as diffuse brown pigmentation. - However, the pigmentation caused by minocycline is typically diffuse or localized to specific areas, and it does not present as "raindrop pigmentation."
Question 3: Loss of intercellular cohesion between keratinocytes is referred to as?
- A. Acanthosis
- B. Acantholysis (Correct Answer)
- C. Keratinolysis
- D. Spongiosis
Explanation: ***Acantholysis*** - This term specifically refers to the **loss of cohesion between keratinocytes** in the epidermis due to the breakdown of desmosomal attachments. - It is a hallmark feature of several **blistering skin diseases**, such as pemphigus. *Acanthosis* - This refers to the **thickening of the stratum spinosum** (prickle cell layer) of the epidermis, often due to an increase in the number of keratinocytes. - It is seen in conditions like **psoriasis** and seborrheic keratosis, but does not involve a loss of intercellular cohesion. *Keratinolysis* - This term describes the **breakdown or dissolution of keratin**, which is the primary structural protein of the epidermis. - While keratinocytes produce keratin, keratinolysis itself is not the specific term for loss of cohesion between these cells. *Spongiosis* - This is defined as **intercellular edema** (fluid accumulation) within the epidermis, especially prominent in the stratum spinosum. - It leads to the widening of intercellular spaces and stretching of desmosomes, but the cells generally remain attached, unlike in acantholysis.
Question 4: Which of the following is NOT a feature of atopic dermatitis?
- A. Dennie-Morgan fold
- B. Darier’s Sign (Correct Answer)
- C. Hyperlinearity of palms
- D. Hertoghe’s sign
Explanation: ***Darier's Sign*** - **Darier's sign** is characteristic of **urticaria pigmentosa** (cutaneous mastocytosis), where rubbing a skin lesion causes the formation of an urticarial wheal due to mast cell degranulation - It is **not associated** with the pathogenesis or clinical presentation of **atopic dermatitis** *Dennie-Morgan fold* - **Dennie-Morgan folds** are extra folds or lines in the skin just below the lower eyelids - They are a common clinical sign observed in patients with **atopic dermatitis**, often linked to chronic inflammation and allergic reactions affecting the skin around the eyes *Hertoghe's sign* - **Hertoghe's sign** refers to the thinning or absence of the lateral third of the eyebrows - This sign is often seen in individuals with **atopic dermatitis**, as well as in other conditions like hypothyroidism *Hyperlinearity of palms* - **Hyperlinearity of palms** refers to the exaggerated creases and lines on the palms of the hands - This is a common **stigmata of atopy** and is frequently observed in patients with **atopic dermatitis**, reflecting the underlying predisposition to skin dryness and altered epidermal barrier function
Question 5: Which of the following skin lesions is not classified as a nevus of melanocytes?
- A. Dysplastic nevus
- B. Congenital melanocytic nevus
- C. Mongolian spot
- D. Becker nevus (Correct Answer)
Explanation: ***Becker nevus*** - A **Becker nevus** is a **hamartoma** of the **epidermis, dermis, and hair follicles**, characterized by increased epidermal basal layer pigmentation and smooth muscle hyperplasia. - While it contains increased **melanin**, it does **not** involve a proliferation of **melanocytes** themselves, differentiating it from true melanocytic nevi. - It is an **organoid hamartoma** with epidermal and dermal components, not a melanocytic lesion. *Mongolian spot* - A **Mongolian spot** is a **dermal melanocytosis** where melanocytes are entrapped in the dermis during their migration from the neural crest to the epidermis. - While technically termed a "melanocytosis" rather than a "nevus," it represents an **ectopic collection of dermal melanocytes** and is classified among melanocytic lesions. - Unlike Becker nevus, it involves an actual abnormal distribution of melanocytes (not just increased melanin). *Congenital melanocytic nevus* - A **congenital melanocytic nevus** is a benign proliferation of **melanocytes** present at birth, involving the dermis and/or epidermis. - These are true **melanocytic nevi**, with a risk of malignant transformation, particularly in larger lesions (>20 cm). *Dysplastic nevus* - A **dysplastic nevus** (atypical nevus) is an atypical melanocytic nevus with architectural and cytological atypia, considered a potential precursor to melanoma. - It is classified as a **melanocytic nevus** due to the proliferation of atypical melanocytes with architectural disorder.
Question 6: Which of the following is NOT a characteristic of dermatophytosis?
- A. Scaly skin
- B. Itchy skin
- C. Superficial infection
- D. Subdermal infection (Correct Answer)
Explanation: ***Subdermal infection*** - Dermatophytosis, or **ringworm**, is characterized by infection of the **superficial keratinized tissues** (skin, hair, nails) and does not typically extend into the subdermal layers. - While fungal infections can be systemic or deep, dermatophytes specifically are restricted to the **stratum corneum** and other dead keratinized structures. *Scaly skin* - **Scaling** is a very common characteristic of dermatophyte infections due to the fungus proliferating within the **stratum corneum**, leading to increased epidermal turnover and shedding. - The scaling can be fine or coarse, often presenting in an **annular (ring-like)** pattern. *Itchy skin* - **Pruritus (itching)** is a prominent symptom of dermatophytosis, often leading patients to seek medical attention. - The itching can range from mild to severe, contributing to discomfort and potential secondary skin excoriations. *Superficial infection* - Dermatophytosis is by definition a **superficial fungal infection**, meaning it is confined to the outermost layers of the skin, hair, and nails. - These fungi produce enzymes such as **keratinases** that allow them to digest keratin, but they generally do not invade viable tissue below the epidermis.
Question 7: Which of the following is the MOST characteristic feature of skin tags (acrochordons)?
- A. They commonly occur on the neck and axilla.
- B. They have malignant potential.
- C. They are associated with seborrhoeic keratosis.
- D. They are typically pedunculated. (Correct Answer)
Explanation: ***They are typically pedunculated.*** - **Skin tags (acrochordons)** are benign soft tissue tumors characterized by their **pedunculated morphology** - they are attached to the skin by a narrow stalk or pedicle. - This **pedunculated appearance** is the **most characteristic** and **defining feature** that distinguishes them from other benign skin lesions. - They are typically **soft, flesh-colored or hyperpigmented**, and range from 1-5 mm in size. *They commonly occur on the neck and axilla.* - While **skin tags** frequently occur in areas of friction such as the neck, axilla, eyelids, groin, and inframammary folds, this **location is not specific**. - Many other skin conditions also favor these sites, so location alone is not a characteristic diagnostic feature. *They are associated with seborrhoeic keratosis.* - There is **no established clinical association** between skin tags and seborrheic keratoses. - Both are common **benign skin growths** in adults but represent different pathological entities with different clinical appearances. *They have malignant potential.* - This is **incorrect**. Skin tags are **benign fibrous polyps** with **no malignant potential**. - They do not require removal unless symptomatic or for cosmetic reasons.
Question 8: Which of the following statements about spider telangiectasia is false?
- A. More common in males (Correct Answer)
- B. Light therapy for treatment
- C. May be associated with liver disease
- D. Can be caused by trauma
Explanation: ***More common in males*** - This statement is **FALSE** because spider telangiectasias (spider nevi/spider angiomas) are more commonly observed in **females**, often due to hormonal influences like **estrogen**. - They are frequently associated with conditions such as **pregnancy**, **oral contraceptive use**, or **chronic liver disease**, highlighting a female predominance. - The estrogen-dependent nature explains their higher prevalence in women of reproductive age. *Can be caused by trauma* - This statement is **TRUE** in a broader sense, though classical spider telangiectasias are primarily hormonally-mediated rather than traumatic. - While **simple telangiectasias** can develop after localized trauma or repeated pressure, spider telangiectasias have a characteristic morphology (central arteriole with radiating vessels) and are typically associated with **estrogen excess** or **liver disease**. - For exam purposes, this is considered a true statement as telangiectatic vessels can be influenced by local factors. *Light therapy for treatment* - This statement is **TRUE**. **Laser therapy**, specifically **pulsed dye laser (PDL)** or **intense pulsed light (IPL)**, is the most effective treatment for spider telangiectasias. - The laser selectively targets **hemoglobin** in the dilated vessels, causing photocoagulation and vessel obliteration, leading to excellent cosmetic results. *May be associated with liver disease* - This statement is **TRUE**. Spider telangiectasias are a well-recognized cutaneous manifestation of **chronic liver disease**, especially **cirrhosis**. - Impaired hepatic function leads to decreased **estrogen metabolism** (hyperestrogenemia), contributing to the development of these vascular lesions. - They are one of the stigmata of chronic liver disease, along with palmar erythema and gynecomastia.
Question 9: In which of the following conditions is the Koebner phenomenon most commonly observed?
- A. Psoriasis (Correct Answer)
- B. Lichen planus
- C. All of the options
- D. Viral warts
Explanation: ***Correct: Psoriasis*** - **Psoriasis** is the **most classic and commonly cited example** of the Koebner phenomenon (isomorphic response) - New psoriatic plaques characteristically develop at sites of cutaneous trauma, scratches, or surgical incisions in 25-50% of psoriasis patients - This is a **pathognomonic feature** frequently tested in competitive exams and considered the prototype condition for demonstrating this phenomenon - The mechanism involves inflammatory cascades triggered by trauma in genetically predisposed skin *Incorrect: Lichen planus* - While lichen planus does exhibit the Koebner phenomenon with purplish polygonal papules appearing along scratch lines, it is **less commonly observed** compared to psoriasis - Seen in approximately 10-25% of lichen planus cases - Not considered the primary example when teaching about Koebner phenomenon *Incorrect: Viral warts* - Viral warts can demonstrate **pseudo-Koebner phenomenon** where new warts form along trauma lines due to viral inoculation - This is more accurately described as **autoinoculation** rather than true isomorphic response - Less commonly discussed in the context of classic Koebner phenomenon compared to psoriasis *Incorrect: All of the options* - While all three conditions can show Koebner-like responses, the question asks for "**most commonly observed**" - Psoriasis remains the **gold standard** and most frequently encountered example in clinical practice and medical literature
Question 10: Which of the following is not a feature of dermatomyositis?
- A. Salmon Patch (Correct Answer)
- B. Periungual telangiectasias
- C. Gottron's patch
- D. Mechanic's hands
Explanation: ***Salmon Patch*** - A **salmon patch** (also known as a nevus simplex or stork bite) is a common, benign vascular birthmark that presents as a flat, red or pink patch. - It is **not associated with dermatomyositis** and has no pathogenic link to the condition. *Gottron's patch* - **Gottron's patches** are a classic cutaneous manifestation of dermatomyositis, characterized by erythematous, violaceous, or dusky red papules or plaques over the **extensor surfaces of the metacarpophalangeal and interphalangeal joints**. - Their presence is highly suggestive of dermatomyositis, often preceding or co-occurring with muscle weakness. *Periungual telangiectasias* - **Periungual telangiectasias** are dilated capillaries around the nail folds and are a common skin manifestation of dermatomyositis. - They represent small vessel vasculopathy, a histological feature, and suggest microvascular damage often seen in systemic connective tissue diseases like dermatomyositis. *Mechanic's hands* - **Mechanic's hands** are a cutaneous feature seen in dermatomyositis (and other inflammatory myopathies like antisynthetase syndrome). - They are characterized by **hyperkeratosis**, fissuring, and scaling of the skin, particularly on the lateral and palmar aspects of the fingers, resembling the hands of a manual laborer.