BG13 Pemphigoid vegetans of the buttocks

Abstract Originally described in 1979, pemphigoid vegetans is an exceptionally rare immunobullous disease, with only a few cases documented in the medical literature to date (Winkelmann RK. Pemphigoid vegetans. Arch Dermatol 1979; 115: 446). We detail the case of an 83-year-old Japanese man, wheelchair bound due to a previous spinal injury, who had an > 15-year history of quiescent bullous pemphigoid. He presented with an 18-month history of pruritic, purplish, scaly plaques on his buttocks, occurring on a background of lymphoedematous changes. On clinical examination, vegetative plaques were noted on the buttocks, against a background of significant lymphoedema. There was no evidence of mucosal involvement. Diagnostic punch biopsies were performed, and histological analysis revealed epidermal hyperplasia with areas of parakeratosis. Spongiosis and moderate inflammation in the dermis were noted, including a mixed inflammatory infiltrate with eosinophils. Additionally, mild oedematous changes were observed in the papillary dermis. Direct immunofluorescence confirmed linear IgG deposition along the basement membrane zone. Despite his skin findings, the patient’s serum eosinophil count was within normal limits. The patient was managed effectively with topical clobetasol propionate 0.5% ointment, leading to significant improvement in both his symptoms and the thickness of the plaques. However, he has experienced intermittent flares, which respond well to the reintroduction of topical therapies. Pemphigoid vegetans remains a poorly understood entity, and its pathogenesis is yet to be elucidated. Reported cases in the literature have involved patients ranging from 9 to 89 years of age, with all individuals presenting with intertriginous vegetative lesions, typically in the inguinal region. Some cases have also demonstrated mucosal involvement and peripheral eosinophilia. The most common pathological findings are epidermal hyperplasia and an eosinophilic infiltrate. Direct immunofluorescence consistently demonstrates linear IgG deposition at the dermoepidermal junction. A variety of treatment modalities have been reported in the literature, including topical corticosteroids, dapsone, tetracyclines and systemic steroids (Kim J, Chavel S, Girardi M, McNiff JM. Pemphigoid vegetans: a case report and review of the literature. J Cutan Pathol 2008; 35: 1144–7). However, the rarity of this condition necessitates further discussion to optimize management strategies.