Papulosquamous disorders: paraphenylenediamine allergy: 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: paraphenylenediamine allergy

Sample item

A woman develops severe oedematous dermatitis of the scalp margin, forehead and eyelids 2 days after using a black hair dye at home. Which allergen should be patch tested first?

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

The answer and the reasoning

A. Paraphenylenediamine

Paraphenylenediamine is the key sensitiser in permanent black hair dyes and temporary black henna. It produces acute facial and scalp dermatitis in a sensitised person. Patch test with PPD is the standard confirmation.

Option by option

  • A. Paraphenylenediamine (correct)

    Correct. Paraphenylenediamine is the classic hair dye allergen.

  • B. Thiuram mix

    Thiuram is a rubber accelerator.

  • C. Nickel sulphate

    Nickel is from jewellery and metal contact.

  • D. Potassium dichromate

    Chromate is from cement and leather.

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, Paraphenylenediamine. Paraphenylenediamine is the key sensitiser in permanent black hair dyes and temporary black henna.

Why is "Thiuram mix" not the answer?

Thiuram is a rubber accelerator.

Why is "Nickel sulphate" not the answer?

Nickel is from jewellery and metal contact.

Why is "Potassium dichromate" not the answer?

Chromate is from cement and leather.

What concept does this question test?

It tests Papulosquamous disorders: paraphenylenediamine allergy in Dermatology. It produces acute facial and scalp dermatitis in a sensitised person. Patch test with PPD is the standard confirmation.

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 Papulosquamous disorders: paraphenylenediamine allergy?

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.