Epidermolysis Bullosa Acquisita — SCE Dermatology MCQ

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HardBlistering DiseasesEpidermolysis Bullosa AcquisitaSCE Dermatology

A mechanobullous eruption heals with scarring and milia over the hands, feet, elbows and knees. Direct immunofluorescence shows linear basement-membrane IgG, and indirect immunofluorescence on salt-split skin binds the dermal floor. Which target is most likely?

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Correct answer: D — Type VII collagen in sublamina-densa anchoring fibrils

Explanation lettering: E = shown as A · A = shown as B · B = shown as C · C = shown as D · D = shown as E

C is correct. The trauma-predominant, scarring, milia-forming phenotype and dermal-floor binding on salt-split skin support epidermolysis bullosa acquisita. Its principal autoantigen is type VII collagen in anchoring fibrils beneath the lamina densa. BP180 and BP230 are hemidesmosomal bullous-pemphigoid antigens that usually bind the epidermal roof. Laminin-332 can produce floor binding in a mucous-membrane-pemphigoid phenotype, so localisation must be integrated with clinical pattern and antigen-specific testing. Desmoglein 1 causes intraepidermal pemphigus foliaceus rather than linear basement-membrane staining. Serration-pattern analysis and immunoblot or ELISA can further resolve difficult cases.

Reference: DermNet epidermolysis bullosa acquisita review: https://dermnetnz.org/topics/epidermolysis-bullosa-acquisita