A Case of Bullous Pemphigoid Arising in a Patient with Prurigo Nodularis

Abstract

A 76-year-old woman presented with a 1-month history of generalized, various sized, excoriated, erythematous papules, and nodules on the trunk and extremities (Fig. 1A), that were accompanied by intense itching. Histopathological findings from the nodular lesions showed irregular epidermal acanthosis, hyperkeratosis, and parakeratosis (Fig. 1B) with negative direct immunofluorescence (DIF), which were consistent with a diagnosis of prurigo nodularis (PN). She was treated with an ihistamines and topical corticosteroids; however, there were no significant improvements in her condition. After 2 months, tense bullae formed at the previous nodular lesion sites (Fig. 2A, B). Re-biopsy showed subepidermal blisters with moderate perivascular inflammatory cell infiltrates that consisted of lymphohistiocytes and a few eosinophils in the dermis (Fig. 2C). DIF revealed linear immunoglobulin G (IgG) and C3 depositions along the basement membrane (Fig. 2D, E). The patient was diagnosed with bullous pemphigoid (BP) developed in PN and was treated with systemic corticosteroids and dapsone. The lesions gradually improved over the course of 5 months.