Parasitic Skin Infections — MCQs

A 65-year-old man presented with skin lesions on his chest and left arm and shoulder, six weeks after returning from a vacation in Belize, where he spent time at the beach in the rainforest. The lesions occasionally stung, drained dark exudates, and enlarged despite two weeks of treatment with cephalexin. The patient had no constitutional symptoms. Physical examination revealed five nodules of varying sizes with surrounding erythema and a central pore through which a single, moving larva was observed. What is the cause of this condition?

Parasitic Skin Infections Indian Medical PG Practice Questions and MCQs

Question 71: Which among the following occupations is a risk factor for cutaneous larva migrans?

A. A poultry worker
B. A kennel worker
C. A lifeguard in a swimming pool
D. Farmer (Correct Answer)

Explanation: ***Farmer*** - Farmers are at high risk due to frequent direct contact with **contaminated soil** or sandy environments where animal feces, especially from dogs and cats, might be present. - Exposure to **larvae of hookworms** such as *Ancylostoma braziliense* and *Ancylostoma caninum*, which can penetrate unprotected skin (e.g., bare feet while working) from the soil. *A lifeguard in a swimming pool* - Lifeguards primarily work in **chlorinated water** or on clean, well-maintained pool decks, which do not typically harbor hookworm larvae. - While they might be exposed to other skin conditions, **cutaneous larva migrans** is not a common risk associated with this occupation. *A poultry worker* - Poultry workers are primarily exposed to avian environments, where hookworm species that cause cutaneous larva migrans in humans are typically **not found**. - Their work environment generally does not involve direct contact with soil contaminated by **canine or feline feces**. *A kennel worker* - While kennel workers handle dogs and cats, which are carriers of hookworms, their primary exposure is to the animals themselves or their immediate cleaned environments, not typically **soil contaminated with larvae**. - The mode of transmission for cutaneous larva migrans is through **soil contact** rather than direct animal handling in a controlled kennel setting.

Question 72: A 65-year-old man presented with skin lesions on his chest and left arm and shoulder, six weeks after returning from a vacation in Belize, where he spent time at the beach in the rainforest. The lesions occasionally stung, drained dark exudates, and enlarged despite two weeks of treatment with cephalexin. The patient had no constitutional symptoms. Physical examination revealed five nodules of varying sizes with surrounding erythema and a central pore through which a single, moving larva was observed. What is the cause of this condition?

A. Cutaneous leishmaniasis
B. Tungiasis
C. Onchocerciasis
D. Bot fly (Correct Answer)

Explanation: ***Bot fly*** - The presence of a **single, moving larva** observed through a central pore in nodular skin lesions, after travel to a tropical region (Belize), is highly characteristic of **myiasis caused by the bot fly (Dermatobia hominis)**. - The symptoms like stinging, dark exudates, and enlargement despite antibiotics are consistent with the larva feeding and growing within the host. *Tungiasis* - Caused by the **sand flea Tunga penetrans**, which burrows into the skin, typically on the feet, causing intense itching and pain. - It presents as a **pigmented nodule** with a central black dot, but **no visible moving larva**. *Cutaneous leishmaniasis* - Presents as **chronic skin ulcers or nodules** that can be slow-healing and often have raised borders. - Diagnosis is confirmed by identifying **amastigotes** in tissue samples, not by observing a moving larva. *Onchocerciasis* - Caused by the filarial nematode **Onchocerca volvulus**, transmitted by blackflies, leading to **subcutaneous nodules (onchocercomas)** and skin changes. - It does not involve a single, macroscopic, moving larva visible through a central pore.

Practice by Chapter

Scabies

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Pediculosis

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Cutaneous Larva Migrans

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Leishmaniasis

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Onchocerciasis

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Myiasis

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Tungiasis

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Cutaneous Amebiasis

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Cutaneous Manifestations of Malaria

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Ectoparasitic Infestations

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Diagnosis of Parasitic Infestations

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Antiparasitic Therapy

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