BP is chronic, accompanied by significant morbidities, clinically characterized by pruritic tense blisters imposed on normal skin or erythematous urticaria-like plaques, and is caused by circulating autoantibodies targeted at structural dermal-epidermal junction components, such as bullous pemphigoid antigen-1 (BP230) and bullous pemphigoid antigen-2 (collagen XVII, BP180) (1–3). This evidence concerns the gene COL17A1 and urticaria.