Oral mucositis-case series of a rare adverse effect associated with immunotherapy

Immune checkpoint inhibitors, such as pembrolizumab and nivolumab, act by inhibiting programmed death-1 and activating the T cells against cancer. An imbalance in this immune response, however, could lead to immune-related adverse events (irAEs) involving multiple organs like rash, fatigue, hypo and hyperthyroidism, pneumonitis, hepatitis, and colitis, among others. Oral irAEs are not uncommon among immune checkpoint inhibitors which include xerostomia, dysgeusia, and lichenoid reactions; however, oral mucositis is rarely seen or reported in patients receiving PD-1 inhibitors. We present 3 cases of this rare complication in varying grades of severity. The patients were managed with steroids, either topical or systemic, depending on the severity of the lesions with either postponement or withholding therapy due to toxicity. Through this article, we hope to bring to light this overlooked and underdiagnosed oral adverse event associated with the use of immunotherapy and various treatment options for its management.