Infections: pityriasis versicolor signs: 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: pityriasis versicolor signs

Sample item

A young man has multiple hypopigmented scaly macules on the upper trunk after sweating in summer. Scratching the surface with a fingernail produces fine scale. What is this sign called?

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

The answer and the reasoning

A. Besnier's sign (scratch or evoked scale sign)

In pityriasis versicolor, due to Malassezia, scraping a macule produces fine bran-like scale; this is Besnier's sign. Wood's lamp shows yellow to apricot fluorescence. KOH shows spaghetti and meatballs, short hyphae with round yeasts.

Option by option

  • A. Besnier's sign (scratch or evoked scale sign) (correct)

    Correct. Scraping a Malassezia macule yields the characteristic scale.

  • B. Koebner phenomenon

    Koebner phenomenon is lesion appearance at sites of trauma.

  • C. Nikolsky sign

    Nikolsky sign is epidermal detachment with lateral pressure in pemphigus.

  • D. Auspitz sign

    Auspitz sign is pinpoint bleeding after scale removal in psoriasis.

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.

More Dermatology questions

Questions about this Dermatology question

What is the answer to this Dermatology question?

The best answer is A, Besnier's sign (scratch or evoked scale sign). In pityriasis versicolor, due to Malassezia, scraping a macule produces fine bran-like scale; this is Besnier's sign.

Why is "Koebner phenomenon" not the answer?

Koebner phenomenon is lesion appearance at sites of trauma.

Why is "Nikolsky sign" not the answer?

Nikolsky sign is epidermal detachment with lateral pressure in pemphigus.

Why is "Auspitz sign" not the answer?

Auspitz sign is pinpoint bleeding after scale removal in psoriasis.

What concept does this question test?

It tests Infections: pityriasis versicolor signs in Dermatology. Wood's lamp shows yellow to apricot fluorescence. KOH shows spaghetti and meatballs, short hyphae with round yeasts.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. 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: pityriasis versicolor signs?

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.