Infections: tinea nigra: practice question

A Dermatology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Dermatology · Infections: tinea nigra

Sample item

A 20-year-old has a solitary, asymptomatic, non-scaly, brown-black macule on the palm after travel to the tropics. KOH shows brown septate hyphae. What is the most likely diagnosis?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

A. Tinea nigra

Tinea nigra is caused by Hortaea werneckii and gives a superficial brownish macule on the palm that can mimic acral melanoma. Brown septate hyphae on KOH confirm it, and topical keratolytics or azoles cure it. Recognition avoids unnecessary excision.

Option by option

  • A. Tinea nigra (correct)

    Correct. Brown hyphae on KOH confirm tinea nigra.

  • B. Acral melanoma

    Melanoma would not show fungal hyphae on KOH.

  • C. Junctional naevus

    A naevus would not show hyphae.

  • D. Addison disease pigmentation

    Addison pigmentation is diffuse with palmar crease accentuation.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

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Questions about this Dermatology question

What is the answer to this Dermatology question?

The best answer is A, Tinea nigra. Tinea nigra is caused by Hortaea werneckii and gives a superficial brownish macule on the palm that can mimic acral melanoma.

Why is "Acral melanoma" not the answer?

Melanoma would not show fungal hyphae on KOH.

Why is "Junctional naevus" not the answer?

A naevus would not show hyphae.

Why is "Addison disease pigmentation" not the answer?

Addison pigmentation is diffuse with palmar crease accentuation.

What concept does this question test?

It tests Infections: tinea nigra in Dermatology. Brown septate hyphae on KOH confirm it, and topical keratolytics or azoles cure it. Recognition avoids unnecessary excision.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Infections: tinea nigra?

Learn each condition by its primary lesion, site and signature sign. Then use the flashcards and the other Dermatology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.