Abstract
The development of immune checkpoint inhibitors is considered to be one of the most important advances in cancer treatment. Pembrolizumab is an immune checkpoint inhibitor against programmed death-ligand 1 (PD-L1) receptor that has demonstrated antineoplastic activity against various malignancies including non-small cell lung cancer, melanoma, and triple-negative breast cancer. Pembrolizumab has been associated with significant dermatological adverse reactions, referred to as immune-related adverse events. The cutaneous adverse effects can affect the quality of life of the patient and can result in dose reduction or even discontinuation of the treatment. Hence it is of utmost importance to have a comprehensive understanding of the cutaneous toxicities for prompt initiation of treatment. We present the case of a 49-year-old male with metastatic non-small cell lung cancer (NSCLC) with 100% PD-L1 expression, who suffered a severe cutaneous reaction involving more than 95% of body surface area, following the first dose of pembrolizumab. He was treated with low-dose systemic steroids (prednisone 10 mg), to which he responded well. Since the patient showed excellent symptomatic and clinical response to pembrolizumab, it was not discontinued. The patient has not developed a rash with subsequent doses of pembrolizumab, and the steroids were tapered off.