Mechanobullous form of epidermolysis bullosa acquisita: Insights into disease mechanisms as inferred by response to rituximab, but not to JAK inhibitors

Epidermolysis bullosa acquisita (EBA) is a rare autoimmune blistering disease associated with IgG autoantibodies directed against type VII collagen. Different clinical forms have been described, including the classical mechanobullous variant resembling epidermolysis bullosa dystrophica, which is typically treatment-resistant. We here describe a 67-year-old patient with a mechanobullous EBA characterized by trauma-induced blisters on her hands and feet for 9 months. Despite treatments with oral prednisolone, topical steroids or calcineurin inhibitors, doxycycline, ciclosporin, and baracitinib, no improvement was observed. The patient went into complete remission only after administration of rituximab with no lesions off therapy at the 10-month follow up. Our observation suggests that inflammatory cytokines are not primarily responsible for skin blistering and fragility in mechanobullous EBA. The effectiveness of rituximab provides some insights into the major direct role of autoantibodies in mediating dermo-epidermal separation in this variant of EBA.