Immune Checkpoint Inhibitors and Systemic Side Effects: Overview for the Inpatient Dermatologist

Purpose of Review: Immune checkpoint inhibitor (ICI) therapy has changed the landscape of cancer treatment and now represents part of the treatment regimen for approximately half of all cancer patients in high-income countries. The nonspecific immune activation of ICIs creates a myriad of adverse effects, most commonly of the skin but also affecting other organ systems with potentially devastating consequences. We aim to highlight the most common or life-threatening systemic toxicities associated with ICIs such that oncodermatologists may be more able to recognize their early clinical signs and symptoms. This knowledge will be helpful in effectively managing follow-up testing and coordinating with other specialty services to improve patient outcomes on ICIs. Recent Findings: In the past 5 years, immune checkpoint inhibitor safety profiles have been updated in several studies and case reports. Multiple guideline statements published by the American Society of Clinical Oncology, the Society for Immunotherapy of Cancer, and the Multinational Association of Supportive Care in Cancer have been recently released on the toxicity management for patients on immune checkpoint inhibitors. These organizations have updated what is known about adverse events for ICIs ranging from gastrointestinal, pulmonary, and hepatic to endocrine complications, as well as immune-mediated cardiovascular, rheumatic, and renal toxicities. Summary: Cutaneous immune-related adverse events to immune checkpoint inhibitor therapies are the most common and earliest complications of these treatment modalities. For the oncodermatologist, recognizing symptoms and signs of rare but dangerous systemic toxicities across various organ systems is important to improve patient outcomes on these therapies.