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Bullous Pemphigoid — SCE Dermatology MCQ

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HardBlistering DiseasesBullous PemphigoidSCE Dermatology

An elderly woman develops tense blisters confined to a breast radiotherapy field. H&E shows a subepidermal split with eosinophils. Which immunopathological result most strongly supports localised bullous pemphigoid rather than pemphigus vulgaris?

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Correct answer: A — Linear basement-membrane-zone IgG and C3 on perilesional direct immunofluorescence

Explanation lettering: C = shown as A · A = shown as C

C is correct. Bullous pemphigoid is a subepidermal autoimmune blistering disease and typically shows linear IgG and C3 at the basement membrane zone on perilesional DIF. Intercellular IgG supports pemphigus; granular papillary IgA supports dermatitis herpetiformis; isolated linear IgA suggests linear IgA disease; full-thickness epidermal necrosis without immunoreactants suggests toxic epidermal necrolysis.

Reference: British Association of Dermatologists: bullous pemphigoid: https://www.bad.org.uk/pils/pemphigoid