Development of bullous pemphigoid during nivolumab therapy

Immune checkpoint inhibitors are a new class of cancer therapeutics that promote antitumor immune responses. Currently US Food and Drug Administration–approved agents target the coregulatory molecules programmed cell death protein 1 (PD-1) and cytotoxic T-lymphocyte–associated protein 4 (CTLA-4) and show significant activity in multiple cancer types. These medications can induce a variety of cutaneous eruptions, the full spectrum of which is not yet completely characterized. Here, we report a case of bullous pemphigoid (BP), which began shortly after initiating treatment with the PD-1 inhibitor nivolumab.