Excimer laser/light treatment of alopecia areata: A systematic review and meta-analyses.

BACKGROUND The excimer laser/light (EL) has been reported to be effective for alopecia areata (AA), but its treatment response has not been systematically reviewed. OBJECTIVE To determine the treatment reponse and safety of EL treatment of AA. METHODS A comprehensive search of the Medline, EMBASE, Cochrane library, and Web of Science (from inception to December 31, 2018) was conducted to identify prospective clinical studies assessing the treatment response of EL for AA. The primary outcome was cosmetically acceptable hair regrowth (hair regrowth ≥75%); random-effects meta-analyses using generic inverse variance weighting were performed to estimate treatment responses. The study was registered with PROSPERO (CRD42019121092). RESULTS Of 52 records initially identified, 13 full-text articles were finally assessed in terms of eligibility. A total of 9 prospective clinical studies (129 AA patients) including 5 controlled clinical trials were identified. Cosmetically acceptable hair regrowth was achieved in 50.2% (95% confidence interval 31.5%-68.9%; 8 studies). EL treatment significantly improved hair regrowth compared to untreated controls (relative risk 7.83; 95% confidence interval 2.11-29.11; 5 controlled clinical trials). No serious adverse effect was noted. CONCLUSIONS EL treatment appeared to produce a favorable therapeutic response in AA patients. The use of EL should be encouraged for AA patients with the advantages of the non-invasiveness and no systemic effect.