Case of localized bullous pemphigoid with unique clinical manifestations in the lower legs

We report the case of a 71-year-old Japanese woman who presented with persistent band-like erosions in the lower legs. Histological examination suggested subepidermal blister formation. Direct and indirect immunofluorescence studies revealed tissue-deposited and circulating immunoglobulin G autoantibodies against the basement membrane. Western blotting revealed autoantibodies to BP230, but not to BP180. Based on these findings, the patient was diagnosed as having a localized type of bullous pemphigoid. We suggest that the unique clinical manifestations in this patient could be attributable to bacterial or fungal infection, and/or mechanical trauma, such as the pressure of her socks.