ABSTRACT
Bullous pemphigoid (BP) is a chronic and recurrent bullous disorder that may be associated with the administration of certain drugs. Recently, bullous cutaneous adverse events after immunotherapy (IT) or targeted therapy have been increasingly reported. Here, we report a case of BP in a patient diagnosed with metastatic melanoma after treatment with pembrolizumab, dabrafenib, and trametinib. Histopathological examination showed a subepidermal blister with perivascular lymphocytic and eosinophilic infiltration; the accompanying findings of linear immunoglobulin G and C3 deposition by immunofluorescence microscopy were consistent with BP. Since IT agents may initiate immune dysregulation and pathologic autoantibody production, which are required for the pathogenesis of BP, the lesions were thought to be cutaneous adverse events caused by IT.