Efficacy and safety of picosecond laser for the treatment of melasma: a systematic review and meta-analysis

Multiple laser modalities have been used for melasma treatment. However, the effectiveness of picosecond laser in treating melasma remains unclear. This meta-analysis investigated the effectiveness and safety of picosecond laser for melasma treatment. Randomized controlled trials (RCTs) comparing picosecond laser with conventional treatment for melasma were searched through five databases. The melasma area severity index (MASI)/modified MASI (mMASI) was used to quantify the degree of melasma improvement. Standardized mean differences and 95% confidence intervals were calculated using Review Manager for result standardization. Six RCTs, which used picosecond laser at 1064, 755, 595, and 532 nm wavelengths, were included herein. Picosecond laser significantly reduced the MASI/mMASI, but the results were highly heterogeneous (P = 0.008, I-2 = 70%). In the subgroup analysis of 1064 and 755 nm picosecond lasers, 1064 nm picosecond laser significantly reduced the MASI/mMASI with no significant side effects (P = 0.04). Meanwhile, 755 nm picosecond laser did not significantly improve the MASI/mMASI compared with topical hypopigmentation agents (P = 0.08) and caused post-inflammatory hyperpigmentation. Other laser wavelengths could not be used in the subgroup analysis owing to an insufficient sample size. Picosecond laser at 1064 nm is safe and effective for melasma treatment. Picosecond laser at 755 nm is not superior to topical hypopigmentation agents in treating melasma. The exact efficacy of other wavelengths of picosecond laser for melasma treatment remains to be verified in large-scale RCTs.