Efficacy and safety of topical agents in the treatment of melasma: What's evidence? A systematic review and meta-analysis.

BACKGROUND

Various topical agents have been used to treat melasma; however, a large-scale evaluation among the currently available treatment is lacking.

OBJECTIVES

The aim of this study was to evaluate the efficacy and safety of topical agents for melasma.

METHODS

The MEDLINE, Embase, Web of Science, Cochrane, and Alt-Healthwatch databases were searched in November 2021. Original studies that reported pre- and post-treatment Melasma Area Severity Index (MASI)/modified Melasma Area Severity Index (mMASI) scores and/or adverse effects (AEs) were eligible for inclusion. The main outcome was the efficacy analyzed by the changes in the pre- and post-treatment with standardized mean difference (SMD) of MASI/mMASI scores; the AEs were calculated with incidence proportion by the reported percentage of skin irritations.

RESULTS

A total of 45 studies (2359 patients) and 55 studies (4539 patients) met the inclusion criteria for efficacy and AEs, respectively. Hydroquinone (HQ) monotherapy (SMD -1.3, 95% CI [-1.6 to -1.0]), HQ-containing combination therapy (-1.4, [-1.7 to -1.1]), cysteamine (-1.6, [-2.0 to -1.2]), tranexamic acid (-1.5, [-2.0 to -1.1]), azelaic acid (-1.3, [-1.7 to -1.0]), and kojic acid (-0.9, [-1.3 to -0.5]) demonstrated comparable efficacy, while zinc sulfate did not exhibit statistically significant improvement (-1.2, [-2.7 to 0.4]). HQ-containing combination therapy (50.9%) and cysteamine (42.2%) demonstrated the highest incidence of irritation, while azelaic acid (18.7%), kojic acid (5.3%), and tranexamic acid (0.8%) revealed a lower risk.

CONCLUSIONS

In this meta-analysis, non-HQ agents except zinc sulfate may be considered as an alternative to HQ-containing agents. However, treatment should be guided by patient's tolerance, availability, and physicians' experience.