Efficacy of cysteamine cream in the treatment of epidermal melasma, evaluating by Dermacatch as a new measurement method: a randomized double blind placebo controlled study

Background: Melasma is a difficult-to-treat hyperpigmentary disorder. Very few studies have been performed regarding the efficacy of cysteamine in the treatment of melasma.Objective: To determine the efficacy of cysteamine cream in the treatment of patients with epidermal melasma using Dermacatch® as a more accurate skin colorimetric measurement tool.Methods: Participating patients (n = 40) received either placebo (n = 20) or cysteamine cream (n = 20) in a double-blind placebo controlled study. Cysteamine cream or placebo was applied on the lesions once a day at bedtime throughout the four-month study period. Treatment efficacy was determined through Dermacatch® and Mexameter® skin colorimetry, MASI scores, Investigator Global Assessments (IGAs), and patient questionnaires, all performed at baseline, 2-month, and 4-month examinations.Results: Prior to the start of the protocol, the mean difference between pigmented and normal skin was calculated for cysteamine and placebo groups using both Dermacatch® (72.3 ± 27.8 and 52.9 ± 16.4, respectively) and Mexameter® (93.6 ± 42.6 and 65.4 ± 22.6, respectively). At 2 months, the mean differences were 38.1 ± 15.3 (Dermacatch®) and 49.9 ± 19 (Mexameter®) in the cysteamine group and 64.9 ± 25.3 (Dermacatch®) and 68 ± 26.2 (Mexameter®) in the placebo group. At 4 months, the mean differences were 23.8 ± 12.9 (Dermacatch®) and 35.5 ± 16.1 (Mexameter®) in the cysteamine group, and 50 ± 18 (Dermacatch®) and 51.2 ± 16.8 (Mexameter®) in the placebo group. Statistically significant differences were found between the cysteamine and placebo group outcomes at both time points (p = .01, p = .02). At the end of the treatment period, MASI scores were significantly lower in the cysteamine group versus placebo (8.03 ± 5.2 vs. 12.2 ± 7.4, p = .04). IGA scores and patient viewpoints indicated significant efficacy of cysteamine cream versus placebo.Conclusion: Cysteamine cream showed significant efficacy in decreasing melanin content of the lesions, as established by Dermacatch® as a new measuring method.