A Late Dermatologic Presentation of Bullous Pemphigoid Induced by Anti-PD-1 Therapy and Associated with Unexplained Neurological Disorder.

Immunotherapy has become the standard of care for various cancer types. The widespread use of immune checkpoints inhibitors confronts us with a whole range of novel immune-related adverse events. Skin toxicity is one of the most frequent adverse events. In this article, we report a case of anti-PD-1 induced late bullous pemphigoid (BP) with mucosal erosions and associated with a troublesome neurological disorder of undetermined origin in a patient with metastatic melanoma. Skin biopsy was essential to make the diagnosis and rapid initiation of systemic prednisolone played a role in favorable clinical outcome of BP. We will discuss the difficulty of early diagnosis of BP, its unusual association with neurological disorders, and the specific management of this particular dermatological entity.