A Case of Psoriasiform Dermatitis Appearing during Administration of Anti-PD-1 Antibody Successfully Treated with Narrow-band UVB Therapy

Abstract

A 78-year-old man had been receiving an anti-PD-1 antibody therapy every 3 weeks for bladder cancer at our hospital. After completing 17 courses of pembrolizumab therapy, erythema developed across the body with severe itching. On skin biopsy of erythema from the left thigh, prolongation of epidermal rete ridges, acanthosis with inltration of neutrophils, and hypogranulosis in the epidermis were observed. Inammatory cell inltration with eosinophils in the dermis was also noted. Therefore, we diagnosed the patient with psoriasiform dermatitis caused by the administration of pembrolizumab. Due to the spread of erythema, pembrolizumab was discontinued and we started topical therapy with corticosteroids and vitamin D3, but the spread of erythema persisted. When narrow-band UVB (NB-UVB) phototherapy was added, erythema slightly faded one month later. Since then, the skin rash has not recurred even with the continuation of pembrolizumab. NB-UVB phototherapy should be considered as a therapeutic option for patients with psoriasiform dermatitis caused by anti-PD-1 antibody treatment. Skin Research, 18 :353-359, 2019