Peeling with retinoic acid in microemulsion for treatment of melasma: A double-blind randomized controlled clinical study

Objective: To evaluate the clinical efficacy of peeling with a microemulsion formulation containing 1% retinoic acid.Materials and Methods: After development of the product, 60 patients with melasma were randomly divided into three groups (n = 20): Group 1-application of conventional 1% retinoic acid peeling (RA 1%). Group 2-application of 1% retinoic acid peeling in microemulsion (RA 1%M). Group 3-Application of placebo. The groups were submitted to four peeling sessions, fortnightly on Days 0, 15, 30, and 45, and analyzed at the time intervals of 0, 15, 30, 45, and 60 days. Evaluation was made by using the Melasma Area and Severity Index (MASI) and Melasma Quality of Life (MelasquoL) instrument. Hemato-biochemical parameters were also evaluated at Days 0 and 60. After obtaining the results, normality was evaluated by means of the Kolmogorov-Smirnov test and afterwards, the following tests were applied: Friedman statistical (to test the effect of the treatments on the MASI index); Wilcoxon, (for comparison between pairs to test the effect of treatments on the MelasQoL index); Kruskal-Wallis, (to test the differences between the groups); and Mann-Whitney, (comparisons between treatments). The level of significance adopted was 5% (alpha = 0.05).Results: The three groups presented a significant reduction in the MASI index, indicating the effect of all the treatments on reducing the melasma (p < 0.001). A significant reduction in the stains was observed with the use of retinoic acid peeling delivered in microemulsion (62%) when compared with the conventional peeling with 1% retinoic acid in a conventional vehicle (26%) and the placebo (12%). There was also a significant reduction in the MelasQoL index (sum of all the aspects) in the three groups, indicating the effect of all the treatments, including the placebo, on the overall quality of life of those with melasma. However, RA 1%M the treatment that promoted the greatest effect on the quality of life of individuals. In percentage terms, the RA 1%M provided a mean reduction of 30% in the MelasQoL index, against 13% of the conventional treatment and only 4% of the placebo. When the hemato-biochemical parameters were compared on Days 0 and 60, there were no significant changes in the results.Conclusion: The chemical peeling performed with RA 1%M was effective for the treatment of melasma, and was shown to be superior to the peeling performed with retinoic acid in a conventional vehicle, in reducing the stains and improving the quality of life of patients.