A 15cm hyperpigmented macule on an adolescent male undergoes changes such as coarseness, growth of hair & acne. Diagnosis is?
What is the most likely diagnosis for a 15 mm hyperpigmented lesion on the shoulder that is enlarging and has hair growing from it?
Schamberg's purpura is seen on?
Which type of ultraviolet radiation causes the most skin disorders?
Potato nose is seen in ?
A 40 year old male reported with recurrent episodes of oral ulcers, large areas of denuded skin and flaccid vesiculo-bullous eruptions. Which is the most important bedside investigation helpful in establishing the diagnosis -
Characteristic of chronic eczema?
Lines of Blaschko are related to?
Scalp and face are involved in-
Dermatophytes affect -
NEET-PG 2013 - Dermatology NEET-PG Practice Questions and MCQs
Question 21: A 15cm hyperpigmented macule on an adolescent male undergoes changes such as coarseness, growth of hair & acne. Diagnosis is?
- A. Melanocytic nevus
- B. Becker nevus (Correct Answer)
- C. Sebaceous nevus
- D. Sebaceous adenoma
Explanation: ***Becker nevus*** - A Becker nevus is a **hyperpigmented patch** that typically appears during adolescence in males, often on the shoulder or upper trunk. - It characteristically becomes **hairy (hypertrichosis)**, more coarse, and can develop acne within the lesion, particularly during puberty due to androgen sensitivity. *Melanocytic nevus* - While melanocytic nevi are hyperpigmented, they generally do not show the characteristic changes of **coarseness, significant hair growth, or acne** within the lesion during adolescence. - They are typically stable in size and texture after initial development, with changes raising concern for **melanoma**. *Sebaceous nevus* - A sebaceous nevus is a **congenital lesion** often appearing as a yellowish-orange, waxy, or bumpy patch, usually on the scalp or face. - It does not typically present as a large, flat hyperpigmented macule that develops hair and acne in adolescence; instead, it may become verrucous or develop tumors in adulthood. *Sebaceous adenoma* - A sebaceous adenoma is a **benign tumor** of the sebaceous glands, usually appearing as a small, solitary, flesh-colored to yellowish papule or nodule, especially on the face. - It is not typically seen as a large, hyperpigmented macule that grows hair and acne over a broad area, as described in the question.
Question 22: What is the most likely diagnosis for a 15 mm hyperpigmented lesion on the shoulder that is enlarging and has hair growing from it?
- A. Melanocytic nevus
- B. Becker nevus (Correct Answer)
- C. Sebaceous nevus
- D. Comedo nevus
Explanation: ***Correct: Becker nevus*** This diagnosis is supported by the description of a **hyperpigmented lesion** that is **enlarging** and has **hair growing from it**, typically appearing during adolescence or young adulthood. **Becker nevus** often presents as an **irregular, hyperpigmented patch**, usually on the shoulder or upper trunk, and is characteristically associated with **hypertrichosis** (increased terminal hair growth). The combination of location (shoulder), enlargement, and hair growth in a 15 mm lesion is classic for Becker nevus. *Incorrect: Melanocytic nevus* While **melanocytic nevi** are hyperpigmented, they typically do not continue to **enlarge significantly** after childhood and generally do not develop new onset **hypertrichosis** as a primary feature. The size (15 mm) and progressive growth combined with hair development are more characteristic of a Becker nevus than a common melanocytic nevus. *Incorrect: Sebaceous nevus* **Sebaceous nevi** are typically **yellow-orange to tan, waxy plaques**, often on the scalp or face, with a cobblestone or papillomatous texture. They are not primarily characterized by **hyperpigmentation** and terminal hair growth, but rather by sebaceous gland proliferation. *Incorrect: Comedo nevus* A **comedo nevus** presents as a linear or unilateral group of **dilated follicular openings** filled with keratinous material, resembling blackheads. It is not characterized by diffuse **hyperpigmentation** or the increased terminal hair growth described in this case.
Question 23: Schamberg's purpura is seen on?
- A. Face
- B. Feet (Correct Answer)
- C. Chest
- D. Arms
Explanation: ***Feet*** - Schamberg's purpura, also known as **progressive pigmented purpuric dermatosis**, most commonly affects the **lower extremities**, particularly the feet and ankles. - The characteristic reddish-brown patches with "cayenne pepper" spots are due to **capillary inflammation** and extravasation of red blood cells. *Face* - While purpura can occur on the face due to other conditions, Schamberg's purpura **rarely presents in this location**. - Facial lesions often suggest different underlying etiologies, such as **vasculitis** or trauma. *Chest* - The chest is an **uncommon site** for Schamberg's purpura. - Involvement of the trunk is less typical compared to the dependent areas of the legs. *Arms* - Although the arms can occasionally be affected, the **feet and lower legs are the predominant sites** for Schamberg's purpura due to factors like **gravity** and hydrostatic pressure. - When present on the arms, it might indicate a more widespread or atypical presentation.
Question 24: Which type of ultraviolet radiation causes the most skin disorders?
- A. UV-A
- B. UV-B (Correct Answer)
- C. UV-C
- D. None of the options
Explanation: ***UV-B*** - **UV-B radiation** is a major cause of **sunburn** and directly damages DNA, leading to most **skin cancers** (basal cell carcinoma, squamous cell carcinoma, and melanoma). - It plays a significant role in photoaging and the development of most **skin disorders** related to sun exposure. *UV-A* - **UV-A radiation** penetrates deeper into the skin than UV-B and is primarily associated with **photoaging**, producing wrinkles and fine lines. - While it contributes to skin cancer development, its direct role in DNA damage and sunburn is less than that of UV-B. *UV-C* - **UV-C radiation** is the most damaging type of UV light, but it is almost entirely **absorbed by the Earth's ozone layer** and does not reach the Earth's surface. - Therefore, it does not typically cause skin disorders in humans under natural conditions. *None of the options* - This option is incorrect because **UV-B radiation** is well-established as a primary cause of numerous skin disorders, including most skin cancers and sunburn.
Question 25: Potato nose is seen in ?
- A. Acne vulgaris
- B. Rhinosporoidosis
- C. Acne rosacea (Correct Answer)
- D. Lupus vulgaris
Explanation: ***Acne rosacea*** - **Potato nose**, also known as **rhinophyma**, is a severe manifestation of **acne rosacea**, characterized by thickened, red, and bumpy skin on the nose. - This condition results from **hyperplasia of sebaceous glands** and connective tissue in the nose, leading to its characteristic bulbous appearance. *Acne vulgaris* - This common skin condition is characterized by **comedones**, **papules**, **pustules**, and sometimes cysts, primarily on the face, chest, and back. - It does **not typically cause rhinophyma** or significant thickening of nasal skin. *Rhinosporoidosis* - This is a **chronic granulomatous fungal infection** affecting mucous membranes, particularly the nose. - While it can cause nasal polyps and masses, it does **not result in the sebaceous gland hyperplasia** and thickened skin characteristic of rhinophyma. *Lupus vulgaris* - Lupus vulgaris is a chronic and progressive form of **cutaneous tuberculosis**, often affecting the face. - It presents with **reddish-brown plaques** and nodules that can ulcerate and scar but does **not lead to the specific nasal hypertrophy** seen in rhinophyma.
Question 26: A 40 year old male reported with recurrent episodes of oral ulcers, large areas of denuded skin and flaccid vesiculo-bullous eruptions. Which is the most important bedside investigation helpful in establishing the diagnosis -
- A. Tzanck smear from the floor of bulla (Correct Answer)
- B. Gram staining of blister fluid
- C. Culture and sensitivity of blister fluid
- D. Skin biopsy with immunofluorescence
Explanation: ***Tzanck smear from the floor of bulla*** - A Tzanck smear from the floor of a bulla will reveal **acantholytic cells** (rounded keratinocytes that have lost their intercellular connections), which are characteristic of pemphigus, consistent with recurrent oral ulcers, denuded skin, and flaccid vesiculobullous eruptions. - This **bedside test** provides a rapid diagnosis by demonstrating the cytological features of acantholysis, differentiating it from other blistering disorders. *Gram staining of blister fluid* - This test is primarily used to identify **bacterial infections** and would show the morphology and Gram-staining characteristics of any bacteria present. - It would not provide information about the **acantholysis** or autoimmune nature of the blistering condition described. *Culture and sensitivity of blister fluid* - This investigation identifies **specific bacterial pathogens** and their antibiotic susceptibilities, which is useful for treating bacterial infections. - It would not help in diagnosing **autoimmune blistering diseases** like pemphigus, where bacteria are not the primary cause of the lesions. *Skin biopsy with immunofluorescence* - While a **skin biopsy with direct immunofluorescence** is the gold standard for confirming pemphigus by detecting autoantibodies, it is an **invasive procedure** requiring laboratory processing and is not considered a rapid bedside investigation. - The question specifically asks for the "most important **bed-side investigation**" helpful in establishing the diagnosis rapidly.
Question 27: Characteristic of chronic eczema?
- A. Erythema
- B. Induration
- C. Lichenification (Correct Answer)
- D. Edema
Explanation: ***Lichenification*** - **Lichenification** is a hallmark of chronic eczema, characterized by thickening of the epidermis with exaggerated skin markings due to persistent rubbing or scratching. - This response reflects the long-term inflammatory and reparative processes in chronically affected skin. *Erythema* - **Erythema**, or redness, is a common finding in both acute and chronic inflammatory skin conditions, including acute eczema, but is not specifically characteristic of chronicity. - While present, it does not distinguish chronic from acute phases as definitively as other features. *Induration* - **Induration** refers to hardening or firmness of the skin, often due to inflammation or infection, and while it can be present in chronic eczema, it's a more general sign and not as specific as lichenification. - It might also suggest other conditions like cellulitis or deep tissue involvement. *Edema* - **Edema**, or swelling, is more prominent in the acute phase of eczema due to vasodilation and increased vascular permeability leading to fluid extravasation. - While some edema can persist, it's a less defining feature of chronic eczema compared to the epidermal changes observed in lichenification.
Question 28: 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 29: Scalp and face are involved in-
- A. Nodular scabies
- B. Infantile scabies (Correct Answer)
- C. Norwegian scabies
- D. Adult scabies
Explanation: ***Infantile scabies*** - In **infants** and young children, scabies can present with widespread lesions, often involving the **head, neck, face, palms, and soles**, unlike in adults. - The immune system in infants is less developed, leading to more generalized and severe manifestations. - This is the characteristic distribution pattern that distinguishes infantile scabies. *Nodular scabies* - Characterized by persistent red-brown **nodules**, typically located in the axillae, groin, and scrotum. - While a variant of scabies, it does not specifically involve the scalp and face as a primary distinguishing feature. - These nodules can persist even after treatment. *Norwegian scabies* - Also called **crusted scabies**, this severe form occurs in immunocompromised patients. - Characterized by **thick, crusted lesions** with millions of mites, highly contagious. - While it can involve extensive body areas including face in immunocompromised hosts, the typical presenting feature is thick crusts, not the predilection for scalp/face seen in infantile scabies. *Adult scabies* - In adults, scabies typically spares the **head and neck** area, affecting interdigital spaces, wrists, elbows, axillae, and groin. - Involvement of the face and scalp is rare in adults, unless they are immunocompromised. - This distribution pattern is the key differentiating feature from infantile scabies.
Question 30: Dermatophytes affect -
- A. Dermis of skin
- B. Keratin (Correct Answer)
- C. Stratum spongiosum
- D. Stratum basale
Explanation: ***Keratin*** - **Dermatophytes** are a group of fungi that have a unique ability to digest **keratin**, a protein found in **skin, hair, and nails**. - This characteristic allows them to colonize and thrive in these superficial tissues, causing infections like **tinea corporis** (ringworm) or **tinea pedis** (athlete's foot). *Dermis of skin* - The **dermis** is the layer of skin beneath the epidermis, rich in **collagen, elastin, blood vessels, and nerves**. - Dermatophytes do not typically invade the dermis; their infections are generally limited to the **stratum corneum** and other keratinized structures. *Stratum spongiosum* - **Stratum spongiosum** is a term sometimes used to describe an edematous (swollen) epidermis, often seen in **eczema** and **dermatitis**. - Dermatophytes do not target this specific architectural change in the epidermis but rather feed on the keratin present in the more superficial layers. *Stratum basal* - The **stratum basale** (also called stratum germinativum) is the deepest layer of the **epidermis**, responsible for cell division and producing new skin cells. - Dermatophytes primarily infect the **dead keratinized cells** of the stratum corneum rather than the metabolically active cells of the stratum basale.