Episodic Neuropathic-Like Musculoskeletal Pain Associated With Ritlecitinib Therapy in Alopecia Universalis: A Case Report.

This case report describes a 30-year-old male patient with extensively treatment-resistant alopecia universalis in the context of autoimmune and atopic comorbidities, including eczema, asthma, severe allergic reactions, and Hashimoto's thyroiditis. The Janus kinase (JAK) inhibitors described in this case report are considered treatment failures, defined as the absence of clinically meaningful hair regrowth after at least six months of therapy or discontinuation due to adverse effects. Despite the recent approval of JAK inhibitors for severe alopecia areata, our patient experienced treatment failure with multiple agents and, while on ritlecitinib, developed a debilitating, episodic musculoskeletal pain syndrome. To our knowledge, such a presentation has not been well characterized in the literature. While causality cannot be firmly established, this case raises the possibility of a novel treatment-related adverse effect that may significantly impair quality of life. These findings underscore the importance of ongoing pharmacovigilance as JAK inhibitors are increasingly utilized in alopecia management.