Papulosquamous disorders: dimethylglyoxime test: 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 · Papulosquamous disorders: dimethylglyoxime test

Sample item

A woman has an itchy eczematous patch under the clasp of her wristwatch and around her navel under a jeans button. Which bedside test would confirm that the metal is the cause?

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

The answer and the reasoning

B. Dimethylglyoxime spot test turning pink

Nickel contact dermatitis causes eczema at sites of contact with metal objects. A dimethylglyoxime spot test turns pink in the presence of released nickel, and patch testing confirms sensitisation.

Option by option

  • A. Potassium hydroxide mount

    A potassium hydroxide mount shows fungal elements and would not identify a metal allergen.

  • B. Dimethylglyoxime spot test turning pink (correct)

    Correct. Dimethylglyoxime turns pink with released nickel.

  • C. Tzanck smear

    A Tzanck smear looks for multinucleated giant cells in herpes or acantholytic cells in pemphigus.

  • D. Wood lamp examination of the patch

    Wood lamp identifies fluorescent pigments or organisms and does not identify metal.

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, Dimethylglyoxime spot test turning pink. Nickel contact dermatitis causes eczema at sites of contact with metal objects.

Why is "Potassium hydroxide mount" not the answer?

A potassium hydroxide mount shows fungal elements and would not identify a metal allergen.

Why is "Tzanck smear" not the answer?

A Tzanck smear looks for multinucleated giant cells in herpes or acantholytic cells in pemphigus.

Why is "Wood lamp examination of the patch" not the answer?

Wood lamp identifies fluorescent pigments or organisms and does not identify metal.

What concept does this question test?

It tests Papulosquamous disorders: dimethylglyoxime test in Dermatology. A dimethylglyoxime spot test turns pink in the presence of released nickel, and patch testing confirms sensitisation.

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 Papulosquamous disorders: dimethylglyoxime test?

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.