DIF Biopsy Site — SCE Dermatology MCQ

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HardBlistering DiseasesDIF Biopsy SiteSCE Dermatology

A mechanobullous eruption shows dermal-floor binding on salt-split skin. Direct immunofluorescence demonstrates a u-serrated pattern. Which antigen is the most likely target?

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Correct answer: C — Type VII collagen

The u-serrated pattern localises immune deposits beneath the lamina densa and is highly characteristic of type VII collagen autoimmunity in epidermolysis bullosa acquisita. Dermal-floor binding alone is less specific and must be interpreted with serration analysis and phenotype.

Reference: https://academic.oup.com/bjd/pages/bad-guidelines