NEET-PG 2013 - Dermatology Practice Questions

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: 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: Wood's lamp has a wavelength of –

360 nm. ***360 nm*** - A **Wood's lamp** emits **long-wave ultraviolet (UV-A) light**, which is typically in the range of 320 to 450 nm. - The precise wavelength of **360 nm** is the most common and effective for dermatological diagnostic applications, allowing visualization of specific fluorescence patterns. *320 nm* - While 320 nm falls within the UV-A spectrum, it is at the lower end and less characteristic of the peak emission wavelength used in Wood's lamps for diagnostic purposes. - Using this lower wavelength might result in less pronounced or absent fluorescence for some conditions. *300 nm* - A wavelength of 300 nm is in the **UV-B spectrum** which is primarily used for therapeutic purposes like **phototherapy for psoriasis**, not for diagnostic fluorescence with a Wood's lamp. - UV-B light has different biological effects and is too short to elicit the characteristic fluorescence observed with a Wood's lamp. *250 nm* - This wavelength falls into the **UV-C spectrum**, which is **germicidal** and harmful to human tissue. - UV-C light is not used in Wood's lamps for diagnostic purposes due to its damaging properties and inability to produce the desired fluorescence.

Question 1

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 2

Potato nose is seen in ?

Accepted Answer

Acne rosacea

Answer

Acne vulgaris

Answer

Rhinosporoidosis

Answer

Lupus vulgaris

Question 3

Scalp and face are involved in-

Accepted Answer

Infantile scabies

Answer

Nodular scabies

Answer

Norwegian scabies

Answer

Adult scabies

Question 4

Wood's lamp has a wavelength of –

Accepted Answer

360 nm

Answer

320 nm

Answer

300 nm

Answer

250 nm

NEET-PG 2013 — Dermatology