The Use of 308-nm Excimer Laser Therapy in Alopecia Areata and Primary Cicatricial Alopecia: A Systematic Review

Background: Lichen planopilaris (LPP) and frontal fibrosing alopecia (FFA) are primary cicatricial alopecias with no FDA-approved treatments and a limited evidence base for any intervention. Alopecia areata (AA), while better studied, similarly lacks a well-tolerated, locally acting non-pharmacologic option. The 308 nm excimer laser is established in inflammatory dermatoses, yet its role in hair loss conditions has not been systematically characterized. This review provides an updated appraisal of the AA evidence base and the first systematic appraisal of excimer therapy in LPP and FFA. Methods: We searched PubMed/Medline, Embase, Web of Science, Scopus, and Cochrane CENTRAL and synthesized findings narratively, given substantial heterogeneity across included studies. Results: In total, 33 studies reporting 634 unique patients met the inclusion criteria across AA subtypes (patchy/localized, totalis, universalis, ophiasic, and pediatric), LPP, and FFA. Most evidence (30/33 studies, 613/634 patients) pertains to AA, where excimer therapy produced meaningful hair regrowth in a large proportion of patients. Cicatricial data was more limited (3/33 studies, 21/634 patients). LPP data suggest improvement in inflammatory symptoms; FFA results were mixed. Adverse effects were mild and transient, primarily erythema and hyperpigmentation. Conclusions: The use of 308 nm excimer therapy may be a well-tolerated non-pharmacologic option when pharmacologic therapy is contraindicated, poorly tolerated, or inadequately effective, though limited evidence, especially for LPP and FFA, warrants further investigation across these and other conditions not yet studied.