Efficacy and safety of cysteamine 5% cream for the management of melasma: a systematic review and meta-analysis of randomized controlled trials.

Currently, hydroquinone serves as topical treatment of choice for melasma. However, its long-term use was associated with melanocyte toxicity. Cysteamine is an aminothiol that possesses antioxidant and depigmenting properties, therefore potentially suitable for treating melasma. This study aims to analyze the efficacy and safety of cysteamine 5% cream for the management of melasma. A comprehensive search was conducted on the Europe PMC, Medline, Scopus, and Cochrane Library databases up until June 22nd, 2024. This review incorporates randomized controlled trials (RCTs) that examines the comparison between cysteamine and placebo or hydroquinone in melasma patients. We employed random-effect models to analyze the odds ratio and standardized mean difference (SMD) for presentation of the outcomes. A total of 7 RCTs were incorporated. The results of our meta-analysis showed cysteamine 5% was more effective than placebo in reducing the Melasma Area and Severity Index (SMD - 0.84; 95% CI - 1.19, - 0.49, p < 0.00001, I = 0%), but showed no significant difference when compared with hydroquinone 4% (SMD 0.16; 95% CI - 0.22, 0.53, p = 0.42, I = 55%). In terms of safety, the incidence of adverse events (AEs) like erythema, irritation, burning, itching, and dryness were higher in the cysteamine 5% than placebo. However, the incidence of these AEs was similar between cysteamine 5% and hydroquinone 4%. This study suggests that cysteamine 5% cream may become suitable alternative of topical hydroquinone for the management of melasma due to similar efficacy and safety profile.