Dupilumab Can Be Effective for Immune-Related Adverse Event Dermatitis: A Case Report and Review of the Literature.

Immune checkpoint inhibitors (ICIs) have significantly improved outcomes in various malignancies but frequently induce immune-related adverse events (irAEs), among which cutaneous irAEs are the most common. Although systemic corticosteroids are the mainstay of treatment, some cases are refractory or difficult to manage due to comorbidities. We report a case of refractory irAE dermatitis successfully treated with dupilumab in a patient with atopic dermatitis (AD) in whom corticosteroid escalation was limited by multiple irAEs. A 79-year-old man with AD, well controlled with lebrikizumab, developed disseminated erythematous eruptions consistent with irAE dermatitis following treatment with carboplatin, etoposide, and atezolizumab for stage IVB small cell lung carcinoma. Although the skin lesions initially improved with systemic corticosteroids, they recurred during tapering. Further escalation of corticosteroids was precluded by the development of ICI-associated pneumonitis, hypothyroidism, and adrenal insufficiency. Given the T helper (Th)2-skewed immune background and the limitations of corticosteroid therapy, dupilumab was initiated. Erythema and pruritus improved rapidly, and near-complete remission was achieved after four doses, enabling discontinuation of systemic corticosteroids. Recent evidence suggests that Th2 cytokines, including IL-4 and IL-13, are involved in ICI-associated dermatitis, supporting the mechanistic rationale for IL-4/IL-13 blockade. This case indicates that dupilumab may represent an effective, steroid-sparing therapeutic option for irAE dermatitis, particularly in patients with an atopic background or in those in whom corticosteroid escalation is limited. Further studies are warranted to clarify its efficacy and clinical positioning.