A retrospective chart review of management strategies for lichenoid eruptions associated with immune-checkpoint inhibitor therapy from a single institution.

Immune checkpoint inhibitors and their associated immune-related cutaneous adverse events are continuing to become a mainstay of cancer treatment regimens. While most rashes are mild and easily manageable, severe or persistent rashes like lichenoid dermatoses can significantly impact the quality of life and may require ICI cessation. Lichenoid dermatoses currently have no management guidelines beyond the use of topical or oral steroids. Our study is a single-institution retrospective chart review to characterize ICI-induced lichenoid eruptions, their treatments, and associated tumor response. We utilized natural language processing and our institutional medical record to identify patients with lichenoid eruptions on ICI therapy. One-hundred nineteen patients were identified, of which 108 rashes were characterized as lichenoid dermatitis and fifteen as lichenoid mucositis. Most patients presented with a diffuse distribution (86%, 101/117), with pruritus in lichenoid dermatoses (82%, 89/108) and pain in lichenoid mucositis (80%, 12/15). Successful treatments for lichenoid dermatitis included topical steroids (81%, 88/108), oral antihistamines (21%, 23/108), and oral steroids (15%, 16/108). Of lichenoid dermatitis patients, 21% (23/108) did not respond to treatment (7) or required oral steroids (16). Approximately 28% of patients who had lichenoid dermatitis had delay, reduction, or discontinuation of their ICI because of their irCAE. This descriptive study highlights the impact of lichenoid dermatitis on patients' ability to remain on ICI therapy and the need for more effective non-steroidal management strategies.