In the linked study, Langan and colleagues determine the incidence of and mortality from bullous pemphigoid and pemphigus vulgaris in the United Kingdom.1 Autoimmune bullous diseases of the skin are potentially life threatening disorders. Autoantibodies are directed against adhesion proteins of the keratinocyte membrane (pemphigus) or proteins of the dermal epidermal junction (bullous pemphigoid). Binding of these antibodies to their target antigens disrupts intraepidermal or dermal epidermal junctions—this often results in the formation of cutaneous or mucosal blisters, which evolve into erosions. Extensive erosion can lead to failure of the skin’s main functions, particularly defence against infection. Treatments aim to block production of pathogenic antibodies by plasma …