Drug eruptions: 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 · Drug eruptions

Sample item

A man repeatedly develops a round, sharply demarcated dusky-red patch on the glans penis within hours of taking a particular antibiotic tablet. Each episode heals with brown pigmentation and recurs at the same site on re-exposure. What is the diagnosis?

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

The answer and the reasoning

C. Fixed drug eruption

Fixed drug eruption recurs at the same site each time the causative drug is taken and typically leaves post-inflammatory hyperpigmentation. Common culprits include cotrimoxazole, tetracyclines and NSAIDs. Stopping the drug is the treatment.

Option by option

  • A. Lichen planus

    Lichen planus has violaceous, flat-topped, itchy papules and is not triggered by single doses.

  • B. Erythema multiforme

    Erythema multiforme shows target lesions at multiple sites and usually follows herpes infection or drugs without fixed recurrence.

  • C. Fixed drug eruption (correct)

    Correct. Recurrence at an identical site with residual pigmentation is the defining feature.

  • D. Allergic contact dermatitis

    Contact dermatitis follows topical exposure and is eczematous, not a dusky well-defined patch after oral tablets.

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 C, Fixed drug eruption. Fixed drug eruption recurs at the same site each time the causative drug is taken and typically leaves post-inflammatory hyperpigmentation.

Why is "Lichen planus" not the answer?

Lichen planus has violaceous, flat-topped, itchy papules and is not triggered by single doses.

Why is "Erythema multiforme" not the answer?

Erythema multiforme shows target lesions at multiple sites and usually follows herpes infection or drugs without fixed recurrence.

Why is "Allergic contact dermatitis" not the answer?

Contact dermatitis follows topical exposure and is eczematous, not a dusky well-defined patch after oral tablets.

What concept does this question test?

It tests Drug eruptions in Dermatology. Common culprits include cotrimoxazole, tetracyclines and NSAIDs. Stopping the drug is the treatment.

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 Drug eruptions?

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.