Immunopathology: dermatitis herpetiformis: practice question

A Pathology 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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Pathology · Immunopathology: dermatitis herpetiformis

Sample item

A 30-year-old man has intensely itchy grouped vesicles on the elbows and knees. His serum tissue transglutaminase antibody is raised. Direct immunofluorescence of uninvolved skin would show which finding?

ALinear IgG along the basement membraneBGranular IgG, IgM and C3 at the dermo-epidermal junctionCGranular IgA deposits in the tips of dermal papillaeDIgG between epidermal cells

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

The answer and the reasoning

C. Granular IgA deposits in the tips of dermal papillae

Dermatitis herpetiformis is the skin manifestation of coeliac disease, with IgA deposits at the dermal papillary tips, and it responds to dapsone and a gluten-free diet. Neutrophilic microabscesses form in the papillae, leading to subepidermal vesicles.

Option by option

A. Linear IgG along the basement membrane
Linear basement membrane IgG indicates bullous pemphigoid.
B. Granular IgG, IgM and C3 at the dermo-epidermal junction
A granular band of several immunoglobulins is the lupus band test in SLE.
C. Granular IgA deposits in the tips of dermal papillae (correct)
Correct. Granular papillary IgA is the diagnostic immunofluorescence finding.
D. IgG between epidermal cells
Intercellular IgG is characteristic of pemphigus.

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.

Questions about this Pathology question

What is the answer to this Pathology question?

The best answer is C, Granular IgA deposits in the tips of dermal papillae. Dermatitis herpetiformis is the skin manifestation of coeliac disease, with IgA deposits at the dermal papillary tips, and it responds to dapsone and a gluten-free diet.

Why is "Linear IgG along the basement membrane" not the answer?

Linear basement membrane IgG indicates bullous pemphigoid.

Why is "Granular IgG, IgM and C3 at the dermo-epidermal junction" not the answer?

A granular band of several immunoglobulins is the lupus band test in SLE.

Why is "IgG between epidermal cells" not the answer?

Intercellular IgG is characteristic of pemphigus.

What concept does this question test?

It tests Immunopathology: dermatitis herpetiformis in Pathology. Neutrophilic microabscesses form in the papillae, leading to subepidermal vesicles.

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 Immunopathology: dermatitis herpetiformis?

Learn each disease as a bundle: cause, key histology, markers, and the clinical hallmark. Then use the flashcards and the other Pathology 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.