NEET-PG 2022 - Dermatology PYQs Practice Questions

Q: A patient presents with annular, scaly, itchy lesions with central clearing. The most likely causative organism is:

Trichophyton rubrum. ***Trichophyton rubrum*** - *Trichophyton rubrum* is the most common dermatophyte causing **tinea corporis** (ringworm), which characteristically presents as **annular, scaly, pruritic plaques with central clearing and an active raised border**. - The inflammatory response to fungal invasion of the stratum corneum produces the characteristic **pruritus and scaling**. - This classic "ringworm" morphology with centrifugal spread and central clearing is pathognomonic for dermatophyte infections. *Sporothrix schenkii* - Causes **sporotrichosis**, presenting as **painless subcutaneous nodules** that follow lymphatic channels (lymphocutaneous pattern). - Lesions are typically nodular and may ulcerate, not annular or scaly. - Usually follows traumatic inoculation, commonly in gardeners or florists. *Mycobacterium leprae* - Causes **leprosy** with **hypopigmented or erythematous patches** showing **loss of sensation** (anesthetic patches). - Nerve involvement leads to sensory loss, making itching uncommon. - The morphology is typically macular patches, not annular plaques with scaling. *Candida albicans* - Causes **intertrigo** and **candidiasis** presenting as **erythematous, moist, macerated patches** with **satellite pustules** in intertriginous areas (skin folds). - While pruritic, the morphology shows beefy-red patches with satellite lesions, not annular scaling plaques. - Typically occurs in warm, moist areas (groin, axillae, under breasts). [Practice more Dermatology PYQs on OnCourse]

Q: A male patient presented with a 0.3 cm nodule on the left nasolabial fold. A pathological examination revealed a basaloid appearance with peripheral palisading. What is the most likely diagnosis?

Basal cell carcinoma. ***Basal cell carcinoma*** - The description of a **basaloid appearance with peripheral palisading** on pathological examination is a classic histological feature of basal cell carcinoma (BCC). - BCC commonly presents as a nodule on sun-exposed areas like the **nasolabial fold** and is the most common skin cancer. *Melanoma* - Melanoma is characterized by the **malignant proliferation of melanocytes** and histologically shows atypical melanocytes with pagetoid spread or nest formation. - While it can appear as a nodule, the described **basaloid appearance with peripheral palisading** is not characteristic of melanoma. *Squamous cell carcinoma* - Squamous cell carcinoma typically shows **atypical keratinocytes** with keratinization, intercellular bridges, and sometimes desmoplasia. - It usually presents as an **erythematous, scaly patch** or nodule, often with ulceration, and the described histology does not match. *Nevus* - A nevus (mole) is a benign proliferation of melanocytes, showing **uniform nests of melanocytes** with maturation as they descend into the dermis. - The term **basaloid appearance** refers to cells resembling basal keratinocytes, which is not typical for a nevus. [Practice more Dermatology PYQs on OnCourse]

Q: A 22-year-old woman presents with diffuse hair loss for 1 month. She had a past history of enteric fever 4 months ago. What is the likely cause?

Telogen effluvium. ***Telogen effluvium*** - **Telogen effluvium** is characterized by diffuse hair shedding, often occurring 2-4 months after a significant physiological or psychological stressor, such as **enteric fever**. - The stress prematurely shifts a large number of hair follicles from the **anagen (growth)** phase into the **telogen (resting)** phase, leading to synchronized shedding. *Androgenic alopecia* - This condition presents as a gradual, patterned hair loss, typically characterized by **receding hairline** and thinning at the crown in men. - In women, it often appears as **diffuse thinning** over the crown, but it's not usually acute or triggered by an infection in the manner described. *Alopecia areata* - **Alopecia areata** is an autoimmune condition causing **sudden, well-demarcated patches of hair loss**, not diffuse shedding. - It is frequently associated with other autoimmune diseases, and the hair loss pattern is distinct from the patient's presentation. *Anagen effluvium* - **Anagen effluvium** causes rapid, diffuse hair loss during the **anagen (growth)** phase, often triggered by chemotherapy or radiation. - The onset is typically much faster (days to weeks) after the trigger, unlike the delayed onset seen in this case. [Practice more Dermatology PYQs on OnCourse]

Q: Pitting of nails is seen in:

Psoriasis and Alopecia areata. ***Psoriasis and Alopecia areata*** - **Nail pitting** is a very common and characteristic finding in **psoriasis**, resulting from defective keratinization of the nail matrix. - While less common, nail pitting can also occur in **alopecia areata**, typically due to inflammation affecting the nail matrix. *Psoriasis only* - While **psoriasis** is a primary cause of nail pitting, stating it as "only" is incorrect as other conditions also present with this sign. - This option incorrectly limits the differential diagnosis for nail pitting. *Psoriasis and Lichen planus* - **Psoriasis** does cause nail pitting, but **lichen planus** typically causes **longitudinal ridging**, splitting, subungual hyperkeratosis, and sometimes pterygium formation, rather than classic pitting. - This option includes a condition that usually manifests with different nail changes. *Alopecia areata and Eczema* - **Alopecia areata** can cause nail pitting, but **eczema** of the hands or fingers more commonly leads to **nail plate dystrophy**, discoloration, ridging, or thickening, rather than distinct pitting. - While eczema can affect nails, pitting is not its characteristic nail manifestation. [Practice more Dermatology PYQs on OnCourse]

Question 1

A patient presents with annular, scaly, itchy lesions with central clearing. The most likely causative organism is:

Accepted Answer

Trichophyton rubrum

Answer

Sporothrix schenkii

Answer

Mycobacterium leprae

Answer

Candida albicans

Question 2

A male patient presented with a 0.3 cm nodule on the left nasolabial fold. A pathological examination revealed a basaloid appearance with peripheral palisading. What is the most likely diagnosis?

Accepted Answer

Basal cell carcinoma

Answer

Melanoma

Answer

Squamous cell carcinoma

Answer

Nevus

Question 3

A 22-year-old woman presents with diffuse hair loss for 1 month. She had a past history of enteric fever 4 months ago. What is the likely cause?

Accepted Answer

Telogen effluvium

Answer

Androgenic alopecia

Answer

Alopecia areata

Answer

Anagen effluvium

Question 4

Pitting of nails is seen in:

Accepted Answer

Psoriasis and Alopecia areata

Answer

Psoriasis only

Answer

Psoriasis and Lichen planus

Answer

Alopecia areata and Eczema

Question 5

A farmer has an ulcer on leg with indurated margin and multiple sinuses with discharging granules. The likely diagnosis is -

Accepted Answer

Mycetoma

Answer

Lupus vulgaris

Answer

Actinomycosis

Answer

Scrofuloderma

NEET-PG 2022 — Dermatology