Leprosy: Lucio phenomenon: 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 · Leprosy: Lucio phenomenon

Sample item

A Mexican patient with diffuse, nonnodular lepromatous leprosy develops painful angular necrotic ulcers on the legs with endothelial invasion by bacilli. What is this reaction called?

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

The answer and the reasoning

B. Lucio phenomenon

The Lucio phenomenon occurs in diffuse lepromatous leprosy and produces ulcerating necrotising vasculitis with bacilli in endothelial cells. Some regard it as a distinct state rather than an immunological reaction type.

Option by option

  • A. Koebner phenomenon

    Koebner phenomenon is isomorphic lesion formation after trauma.

  • B. Lucio phenomenon (correct)

    Correct. This is the Lucio phenomenon.

  • C. Type 1 reaction

    Type 1 reaction is a delayed hypersensitivity in borderline leprosy.

  • D. Erythema nodosum leprosum

    ENL shows tender subcutaneous nodules with systemic illness.

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, Lucio phenomenon. The Lucio phenomenon occurs in diffuse lepromatous leprosy and produces ulcerating necrotising vasculitis with bacilli in endothelial cells.

Why is "Koebner phenomenon" not the answer?

Koebner phenomenon is isomorphic lesion formation after trauma.

Why is "Type 1 reaction" not the answer?

Type 1 reaction is a delayed hypersensitivity in borderline leprosy.

Why is "Erythema nodosum leprosum" not the answer?

ENL shows tender subcutaneous nodules with systemic illness.

What concept does this question test?

It tests Leprosy: Lucio phenomenon in Dermatology. Some regard it as a distinct state rather than an immunological reaction type.

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 Leprosy: Lucio phenomenon?

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.