Anti-PD1 immune checkpoint inhibitor-induced bullous pemphigoid in metastatic melanoma and non-small cell lung cancer.

Anti-programmed cell death 1 (PD1) targeted immune checkpoint inhibitors such as nivolumab and pembrolizumab are increasingly used to treat advanced malignancies such as melanoma, non-small cell lung cancer, urothelial cancer, and renal cell carcinoma. A rare but increasingly reported adverse effect of anti-PD1 therapy is bullous pemphigoid (BP), an autoimmune blistering disease directed against BP antigen 1 and BP antigen 2 in the basement membrane of the epidermis. We present 3 cases of BP secondary to anti-PD1 immunotherapy in patients with melanoma and non-small cell lung cancer to highlight the diagnosis and treatment of this condition and emphasize the importance of the dermatologist in the care of patients with immunotherapy-related skin disease.