Cutaneous adverse events due to immune checkpoint inhibitors

Immune checkpoint inhibitors, represented by anti-PD-1 antibodies, anti-PD-L1 antibodies and anti-CTLA-4 antibodies, have brought significant therapeutic benefits to many patients with advanced-stage malignancies. By releasing inhibitory signals on T cells, these agents enhance antitumor immune responses and have dramatically improved clinical outcomes in various cancers. However, this immune activation is accompanied by increased autoimmunity, resulting in a wide spectrum of immune-related adverse events (irAEs). Among these, cutaneous irAEs are the most frequent and encompass diverse clinical subtypes, including maculopapular, lichenoid, psoriasiform and bullous eruptions. Although their precise pathophysiology remains incompletely understood, disruption of immune self-tolerance is thought to play a central role. In this review, we summarize the clinical characteristics of cutaneous irAEs and discuss their potential immunological mechanisms.