NEET-PG 2013 - Dermatology Practice Questions

Q: A 15cm hyperpigmented macule on an adolescent male undergoes changes such as coarseness, growth of hair & acne. Diagnosis is?

Becker nevus. ***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.

Q: What is the most likely diagnosis for a 15 mm hyperpigmented lesion on the shoulder that is enlarging and has hair growing from it?

Becker nevus. ***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.

Q: Schamberg's purpura is seen on?

Feet. ***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.

Q: Which type of ultraviolet radiation causes the most skin disorders?

UV-B. ***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.

Q: Potato nose is seen in ?

Acne rosacea. ***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.

Q: 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 -

Tzanck smear from the floor of bulla. ***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.

Q: Characteristic of chronic eczema?

Lichenification. ***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.

Q: Lines of Blaschko are related to?

Keratinocytes. ***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**.

Q: Scalp and face are involved in-

Infantile scabies. ***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.

Q: Dermatophytes affect -

Keratin. ***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.

Question 1

A 15cm hyperpigmented macule on an adolescent male undergoes changes such as coarseness, growth of hair & acne. Diagnosis is?

Accepted Answer

Becker nevus

Answer

Melanocytic nevus

Answer

Sebaceous nevus

Answer

Sebaceous adenoma

Question 2

What is the most likely diagnosis for a 15 mm hyperpigmented lesion on the shoulder that is enlarging and has hair growing from it?

Accepted Answer

Becker nevus

Answer

Melanocytic nevus

Answer

Sebaceous nevus

Answer

Comedo nevus

Question 3

Schamberg's purpura is seen on?

Accepted Answer

Feet

Answer

Face

Answer

Chest

Answer

Arms

Question 4

Which type of ultraviolet radiation causes the most skin disorders?

Accepted Answer

UV-B

Answer

UV-A

Answer

UV-C

Answer

None of the options

Question 5

Potato nose is seen in ?

Accepted Answer

Acne rosacea

Answer

Acne vulgaris

Answer

Rhinosporoidosis

Answer

Lupus vulgaris

Question 6

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 -

Accepted Answer

Tzanck smear from the floor of bulla

Answer

Gram staining of blister fluid

Answer

Culture and sensitivity of blister fluid

Answer

Skin biopsy with immunofluorescence

Question 7

Characteristic of chronic eczema?

Accepted Answer

Lichenification

Answer

Erythema

Answer

Induration

Answer

Edema

Question 8

Lines of Blaschko are related to?

Accepted Answer

Keratinocytes

Answer

Blood vessels

Answer

Nerves

Answer

Bones

Question 9

Scalp and face are involved in-

Accepted Answer

Infantile scabies

Answer

Nodular scabies

Answer

Norwegian scabies

Answer

Adult scabies

Question 10

Dermatophytes affect -

Accepted Answer

Keratin

Answer

Dermis of skin

Answer

Stratum spongiosum

Answer

Stratum basale

NEET-PG 2013 — Dermatology