Bullous pemphigoid (BP) is a senile autoimmune blistering disease with autoantibodies against the basement membrane. Less than 20 cases of localized BP in young adults have been reported and the understanding of localized BP is very limited. An unusual location of localized BP is here described. A 30-year-old woman presented with a 4-month history of itchy erythema on her trunk. The lesion, well-demarcated erythema and maculopapules in bra's shape, had been misdiagnosed as contact dermatitis. Laboratory finding was notable for serum autoantibodies to BP antigen 180 (BP180). Histopathological examination revealed a subepidermal blister with eosinophils and neutrophils infiltration. Salt-split indirect immunofluorescence revealed linear deposition of IgG at the dermoepidermal junction. After treating her with minocycline 200 mg and nicotinamide 1,500 mg per day, all lesions resolved within 1 month. Localized BP is usually misdiagnosed. It starts from various triggers and has a more benign disease course. It should be emphasized that a long-term follow-up of patients with localized BP may be important for management of the chronic disease, given a relatively high risk of developing generalized BP.
Keywords: Bullous pemphigoid (BP); case report; diagnosis; mechanism.
2020 Annals of Translational Medicine. All rights reserved.