PURPOSE: Antibiotic use in acne treatment raises concerns about increased resistance, necessitating alternatives. We assessed the effectiveness of blue-light therapy for acne.
METHODS: We analyzed randomized controlled trials comparing blue light with nonlight interventions. Studies included people of any age, sex, and acne severity, in any setting, and reported on investigator-assessed change in acne severity, patients' assessment of improvement, change in inflammatory or noninflammatory lesions, and adverse events. Where data were sufficient, mean differences were calculated.
RESULTS: Eighteen references (14 trials) including 698 participants were included. Most of the trials were small and short (<12 weeks) and had high risk of bias. Investigator-assessed improvement was quantitatively reported in 5 trials, of which 3 reported significantly greater improvement in blue light than comparator, and 2 reported improvement. Patients' assessments of improvement were quantitatively reported by 2 trials, favoring blue light. Mean difference in the mean number of noninflammatory lesions was nonsignificant between groups at weeks 4, 8, and 10-12 and overall (mean difference [MD] = 3.47; 95% CI, -0.76 to 7.71; P = 0.11). Mean difference in the mean number of inflammatory lesions was likewise nonsignificant between groups at any of the time points and overall (MD = 0.16; 95% CI, -0.99 to 1.31; P = 0.78). Adverse events were generally mild and favored blue light or did not significantly differ between groups.
CONCLUSION: Methodological and reporting limitations of existing evidence limit conclusions about the effectiveness of blue light for acne. Clinicians and patients should therefore consider the balance between its benefits and adverse events, as well as costs.