Bullous disorders: pemphigus immunofluorescence: 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 · Bullous disorders: pemphigus immunofluorescence

Sample item

Direct immunofluorescence of perilesional skin in pemphigus vulgaris shows which pattern?

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

The answer and the reasoning

C. Intercellular IgG and C3 in a net-like (fishnet) pattern

Binding of IgG to desmosomal cadherins outlines keratinocytes, giving a chicken-wire or fishnet pattern. This is the gold standard test, taken from perilesional skin.

Option by option

  • A. Granular IgA in dermal papillary tips

    Granular IgA in dermal papillae is dermatitis herpetiformis.

  • B. Band of IgG and IgM at the dermoepidermal junction

    A band of immunoglobulins at the junction is the lupus band test.

  • C. Intercellular IgG and C3 in a net-like (fishnet) pattern (correct)

    Correct. Intercellular IgG deposition gives the fishnet pattern.

  • D. Linear IgG and C3 along the basement membrane

    Linear IgG and C3 at the basement membrane is bullous pemphigoid.

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, Intercellular IgG and C3 in a net-like (fishnet) pattern. Binding of IgG to desmosomal cadherins outlines keratinocytes, giving a chicken-wire or fishnet pattern.

Why is "Granular IgA in dermal papillary tips" not the answer?

Granular IgA in dermal papillae is dermatitis herpetiformis.

Why is "Band of IgG and IgM at the dermoepidermal junction" not the answer?

A band of immunoglobulins at the junction is the lupus band test.

Why is "Linear IgG and C3 along the basement membrane" not the answer?

Linear IgG and C3 at the basement membrane is bullous pemphigoid.

What concept does this question test?

It tests Bullous disorders: pemphigus immunofluorescence in Dermatology. This is the gold standard test, taken from perilesional skin.

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 Bullous disorders: pemphigus immunofluorescence?

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.