The life-threatening rash of immune checkpoint inhibitor therapy

Immune checkpoint inhibitors (ICPi) have emerged as a new frontier of cancer therapy. Although monoclonal antibodies to cytotoxic T-lymphocyte associated protein 4 (CTLA-4), programmed cell death 1 (PD-1), and programmed cell death ligand 1 (PD-L1) have revolutionized oncologic management, these agents may result in a spectrum of immune-related adverse events (irAE) of which dermatologic toxicities are among the most frequent. Prompt recognition and management of irAE is essential for dermatologists caring for the expanding population of cancer patients exposed to these drugs. Cutaneous toxicities range from mild cases to severe and life-threatening presentations that may cause significant morbidity and mortality. This review provides an overview of severe cutaneous adverse reactions (SCARs) that may develop during ICPi therapy, including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), drug reaction with eosinophilia and systemic symptoms (DRESS), and acute generalized exanthematous pustulosis (AGEP). In addition, immunobullous disorders, erythroderma, neutrophilic dermatoses, and cutaneous eruptions associated with systemic manifestations are discussed.