Treatment of Psoriasiform Drug Eruptions in Patients on Immune Checkpoint Inhibitors

Abstract

Immune checkpoint inhibitors are increasingly used in oncology, including in Canada. Pembrolizumab alone is Health Canada-approved for at least 15 distinct cancer types. Cutaneous immune-related adverse events (irAEs) are the most common toxicities associated with immune checkpoint inhibitors, occurring in more than 30% of patients. These reactions impair quality of life and can lead to temporary interruption or permanent cessation of these potentially lifesaving therapies. With their increasing use, dermatologists in community practice, not only those in tertiary centres, are likely to encounter affected patients, and are well placed to improve both quality of life and treatment outcomes. The goal of this article is to review practical, community-based management strategies, with a focus on systemic therapy selection and oncologic safety.

Cutaneous irAEs comprise a wide range of clinical presentations, including maculopapular rash, pruritus, blistering disorders, lichenoid diseases, psoriasiform diseases, inflammation of the oral mucosa, and sicca syndrome/oral dysesthesia. Psoriasiform diseases account for approximately 23% of cutaneous irAEs, and are most strongly associated with programmed death-1/programmed death-ligand 1 (PD-1/PD-L1) inhibitor monotherapy. Notably, psoriasiform irAEs are unique in that systemic steroids are not part of the latest National Comprehensive Cancer Network (NCCN) treatment algorithm, given concerns about the risk of pustular rebound flares. In clinical practice, patients with moderate‑to-severe disease are referred to dermatology for assistance with non-steroid systemic treatments.