PD-1 inhibitor induced alopecia areata.

Immune checkpoint modulators are becoming more prevalent in clinical use for the treatment of metastatic melanoma and other malignancies. These drugs, including programmed death 1 (PD-1) inhibitors, have a high incidence of immune adverse events, including cutaneous manifestations. Alopecia is a known side effect with these drugs, but previous reports describe chemotherapy-induced alopecia. We report a case of alopecia areata in a patient on monotherapy with pembrolizumab (PD-1 inhibitor). It is important for the dermatologist to recognize and appropriately treat to decrease morbidity for these patients.