Vesiculobullous disorders: autoantigen in dermatitis herpetiformis: 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 · Vesiculobullous disorders: autoantigen in dermatitis herpetiformis

Sample item

Granular IgA deposits at the tips of dermal papillae are found in a man with intensely itchy grouped vesicles over the elbows and knees. Which is the main target antigen of this IgA?

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

The answer and the reasoning

B. Epidermal transglutaminase

In dermatitis herpetiformis, IgA is directed against epidermal transglutaminase (TG3), which is the skin counterpart of tissue transglutaminase in coeliac disease. The antibodies form granular deposits at the dermal papillary tips, and dapsone plus a gluten-free diet are the treatment.

Option by option

  • A. Desmoglein 1

    Desmoglein 1 is the target in pemphigus foliaceus with intercellular IgG.

  • B. Epidermal transglutaminase (correct)

    Correct. Epidermal transglutaminase is the principal antigen in the skin.

  • C. Bullous pemphigoid antigen 180

    BP180 is the target in bullous pemphigoid and gives linear deposition.

  • D. Type VII collagen

    Type VII collagen is the target of IgG in epidermolysis bullosa acquisita.

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, Epidermal transglutaminase. In dermatitis herpetiformis, IgA is directed against epidermal transglutaminase (TG3), which is the skin counterpart of tissue transglutaminase in coeliac disease.

Why is "Desmoglein 1" not the answer?

Desmoglein 1 is the target in pemphigus foliaceus with intercellular IgG.

Why is "Bullous pemphigoid antigen 180" not the answer?

BP180 is the target in bullous pemphigoid and gives linear deposition.

Why is "Type VII collagen" not the answer?

Type VII collagen is the target of IgG in epidermolysis bullosa acquisita.

What concept does this question test?

It tests Vesiculobullous disorders: autoantigen in dermatitis herpetiformis in Dermatology. The antibodies form granular deposits at the dermal papillary tips, and dapsone plus a gluten-free diet are 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 Vesiculobullous disorders: autoantigen in dermatitis herpetiformis?

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.