Metabolic skin signs: friction melanosis: 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 · Metabolic skin signs: friction melanosis

Sample item

A young Indian woman has a symmetric, rippled brown pigmentation over the interscapular region that appeared after years of vigorous scrubbing with a nylon bath towel. What is the likely diagnosis?

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

The answer and the reasoning

B. Macular amyloidosis (friction melanosis)

Macular amyloidosis shows a rippled brown pigmentation of the upper back, often linked to repeated friction such as from nylon towels. Biopsy shows amyloid in the papillary dermis. Avoiding friction and using sunscreen and topical agents helps.

Option by option

  • A. Tinea versicolor

    Tinea versicolor has fine scale and fungal elements.

  • B. Macular amyloidosis (friction melanosis) (correct)

    Correct. Rippled interscapular pigmentation after friction suggests macular amyloidosis.

  • C. Acanthosis nigricans

    Acanthosis nigricans is velvety and flexural.

  • D. Addison disease

    Addison disease causes diffuse pigmentation with mucosal involvement.

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 B, Macular amyloidosis (friction melanosis). Macular amyloidosis shows a rippled brown pigmentation of the upper back, often linked to repeated friction such as from nylon towels.

Why is "Tinea versicolor" not the answer?

Tinea versicolor has fine scale and fungal elements.

Why is "Acanthosis nigricans" not the answer?

Acanthosis nigricans is velvety and flexural.

Why is "Addison disease" not the answer?

Addison disease causes diffuse pigmentation with mucosal involvement.

What concept does this question test?

It tests Metabolic skin signs: friction melanosis in Dermatology. Biopsy shows amyloid in the papillary dermis. Avoiding friction and using sunscreen and topical agents helps.

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 Metabolic skin signs: friction melanosis?

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.