Bullous pemphigoid associated with anti-programmed cell death protein 1 and anti-programmed cell death ligand 1 therapy: A review of the literature

Abstract

Bullous pemphigoid constitutes a rare dermatological immune-related adverse event of programmed cell death protein 1 (PD-1)/programmed cell death ligand 1 (PD-L1) inhibitors. Herein, we review all published cases of anti-PD-1/PD-L1 related bullous pemphigoid and discuss current knowledge on this condition. Clinical and diagnostic findings were found to resemble those of classic bullous pemphigoid. A delayed onset of bullous pemphigoid after commencement of immun-otherapy as well as a frequent precendence of a refrac-tory pruritic eruption prior to blister development was oberved, both posing diagnostic challenges. In addi-tion to topical and systemic treatment, most patients required either discontinuation or permanent inter-ruption of immunotherapy. Assessment of tumour outcome did not reveal improved survival in patients developing bullous pemphigoid during immuno-therapy, as suggested for other types of skin toxicity, including vitiligo. Better understanding of the patho-genetic mechanism and prognostic implications of this increasingly-reported adverse event is essential in order to establish optimal diagnostic and therapeutic management of these patients.