Localized Bullous Pemphigoid Triggered by Surgical Trauma: A Case Highlighting the Koebner Phenomenon.

Bullous pemphigoid (BP) is the most common autoimmune blistering disease in the elderly. Although usually spontaneous, it may be triggered by skin trauma. We report the case of a 90-year-old woman who developed localized BP along a surgical scar one month after orthopedic surgery. Lesions later spread to the trunk. Histology revealed a subepidermal blister with eosinophils, and immunofluorescence confirmed C3 deposition in addition to circulating anti-BP180 antibodies. Clinical improvement was observed following the initiation of topical corticosteroid therapy.