LAUSR

L‐Cysteamine is a biological antioxidant produced during the coenzyme A metabolism cycle and is naturally present in all mammalian cells. The efficacy of topical cysteamine for the treatment of melasma has been recently shown in two double‐blind, randomized, and placebo‐controlled clinical trials. Herein, we report a 44‐year‐old patient with melasma resistant to Kligman's formula (Pigmanorm cream), who was successfully treated with topical cysteamine as a new depigmenting agent. Skin colorimetric measurements, MASI score determination, and standard photographies after 2 and 4 months of once daily application of cysteamine cream showed a marked improvement of the hyperpigmented lesions. Telangiectasia and perilesional hypopigmentation improved rapidly after the discontinuation of Kligman's formula and starting the treatment with topical cysteamine. After 4 months, the therapeutic results were maintained through a biweekly application regimen of cysteamine cream. The use of cysteamine cream was well tolerated and did not induce any side effects during the 3‐year follow‐up of the patient. Cysteamine is a natural molecule with an excellent safety profile and known antimutagenic, antimelanoma, and anticarcinogenic effects. Considering the high efficacy of cysteamine cream, it is possible that it could replace mutagenic and carcinogenic depigmenting agents such as hydroquinone in near future.