Leflunomide: An Unlikely Trigger and Mechanistically a Beneficial Drug for Alopecia Areata

The letter to the editor challenges the notion that leflunomide causes alopecia areata (AA), arguing instead that it may be a beneficial treatment for the condition. The authors point out that drug-induced AA is rare and usually associated with chemotherapeutic drugs, not leflunomide. They note that the case in question linked the onset of AA to leflunomide after 9 months, which is unlikely, and that the resolution of AA could be due to an increased dose of methotrexate, a known treatment for AA. The authors also mention that in their clinic, out of approximately 400 patients treated with leflunomide, none developed AA, suggesting no strong link between the drug and AA. They propose that AA is more likely an autoimmune manifestation in predisposed individuals. The authors highlight leflunomide's potential as a novel therapy for AA, as it modulates the JAK-STAT pathway, increases TGF-ß levels, inhibits immune cell migration, stimulates regulatory cells, and has shown to promote hair growth in animal studies. They conclude that the role of leflunomide in causing AA should be re-examined unless rigorously proven.