Atezolizumab Caused Pityriasis Lichenoides-Like Drug Eruption Treated with Narrowband Ultraviolet B

Pityriasis lichenoides is a rare cutaneous disease that exists along a spectrum with acute and chronic features. The acute form, pityriasis lichenoides et varioliformis acuta (PLEVA), presents as a sudden onset scaly and often crusted, erythematous papular eruption. The chronic form, pityriasis lichenoides chronica, presents similarly but with a more indolent onset. This inflammatory condition can have numerous triggers, including infections and medications. However, checkpoint inhibitors, despite being associated with a wide variety of cutaneous adverse events, have only rarely been associated with a pityriasis lichenoides-like eruption. We report a case of drug-induced pityriasis lichenoides-like eruption secondary to checkpoint inhibitor atezolizumab that was successfully treated with narrowband ultraviolet B (NBUVB) light. To our knowledge, this is the first case of an atezolizumab-induced pityriasis lichenoides which responded well to NBUVB.