Papulosquamous disorders: lichen planus pemphigoides: 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: lichen planus pemphigoides

Sample item

A man with itchy violaceous flat-topped papules on the wrists develops tense blisters both over the papules and on clinically normal skin of the limbs. Direct immunofluorescence shows linear C3 and IgG along the basement membrane zone. What is the diagnosis?

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

The answer and the reasoning

C. Lichen planus pemphigoides

Lichen planus pemphigoides combines features of lichen planus with a subepidermal bullous disease, with autoantibodies mainly to the NC16A region of BP180. Blisters arise on normal skin as well as on lesions, and DIF shows linear basement membrane deposits. Bullous lichen planus, by contrast, has blisters only on lichen planus lesions and no linear deposits.

Option by option

  • A. Pemphigus vulgaris

    Pemphigus vulgaris gives flaccid blisters and an intercellular, fishnet IgG pattern.

  • B. Bullous lichen planus

    Bullous lichen planus blisters arise only on existing lesions from severe basal damage, with no linear IgG.

  • C. Lichen planus pemphigoides (correct)

    Correct. Blisters on normal skin plus linear basement membrane deposits mean a pemphigoid-type overlap.

  • D. Dermatitis herpetiformis

    Dermatitis herpetiformis shows granular IgA in the dermal papillae.

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 C, Lichen planus pemphigoides. Lichen planus pemphigoides combines features of lichen planus with a subepidermal bullous disease, with autoantibodies mainly to the NC16A region of BP180.

Why is "Pemphigus vulgaris" not the answer?

Pemphigus vulgaris gives flaccid blisters and an intercellular, fishnet IgG pattern.

Why is "Bullous lichen planus" not the answer?

Bullous lichen planus blisters arise only on existing lesions from severe basal damage, with no linear IgG.

Why is "Dermatitis herpetiformis" not the answer?

Dermatitis herpetiformis shows granular IgA in the dermal papillae.

What concept does this question test?

It tests Papulosquamous disorders: lichen planus pemphigoides in Dermatology. Blisters arise on normal skin as well as on lesions, and DIF shows linear basement membrane deposits. Bullous lichen planus, by contrast, has blisters only on lichen planus lesions and no linear deposits.

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: lichen planus pemphigoides?

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.