Clinical response and time to improvement with 308-nm excimer laser therapy in scarring alopecia: a retrospective cohort study

PURPOSE: Excimer laser therapy, a 308-nm narrowband UV-B modality, has shown promise in inflammatory dermatoses, but remains understudied in scarring alopecia (SA). MATERIALS AND METHODS: We conducted an IRB-approved retrospective study of adults with SA treated with excimer therapy to characterize clinical outcomes, response timelines, and treatment patterns. RESULTS: . After a mean of 3.4 months, 60% of patients reported subjective improvement in hair or hairline appearance. Symptomatic improvements were observed in scalp pain (100%), burning (75%), and pruritus (50%), generally within two to six months. Signs of inflammation, including perifollicular hyperkeratosis and erythema, improved in 83% of affected patients. Trichoscopic measures of hair density and shaft caliber remained stable, suggesting disease stabilization without accelerated follicular loss. Adverse effects were common but mild, including erythema, burning, and pain, and did not lead to koebnerization. CONCLUSIONS: Overall, excimer therapy was well-tolerated and associated with meaningful clinical and symptomatic improvement. These findings support excimer therapy as a potentially effective adjunctive treatment for inflammatory control and stabilization in SA, with response typically occurring within the first several months of therapy.