Background: Melasma is a common disfiguring skin problem. Multiple modalities have been used in the treatment of melasma, such as bleaching agents and chemical peels. Many chemicals have been used in the skin peeling for melasma, such as Jessner's solution and glycolic acid. Lactic acid is an alpha-hydroxy acid that has not been used before in chemical peeling of melasma.
Objective: The purpose of the present work is to evaluate the efficacy and safety of lactic acid in chemical peeling of melasma.
Methods: This study was conducted at the outpatient Department of Dermatology and Venereology, Baghdad Teaching Hospital, in the period between April 2001 and August 2002. Twenty patients with melasma were included in this study; 18 (90%) were female and 2 (10%) were male, with an age range from 24 to 38 years and a mean of 29 +/- 4.264 SD. Full clinical examination was done of all patients, including Wood's light. The severity of melasma was assessed by the Melasma Area Severity Index (MASI). Pure lactic acid, full strength (92%; pH 3.5), was used as a new peeling agent. The chemical peeling sessions were done every 3 weeks until the desired response was achieved, but not more than six sessions. Follow-up was carried out for 6 months after the last session. All patients had skin type IV; morphologic forms of melasma were a mask-like shape in seven patients (35%), a butterfly shape in nine patients (45%), and a horseshoe shape in 4 patients (20%).
Results: Eight patients defaulted from the study after the first session for unknown reasons. Twelve patients completed the study. Eleven patients were female (91.7%), and one patient was male (8.3%). Their ages ranged from 24 to 38 years, with a mean of 29.25 +/- 4.9 SD. Wood's light examination showed increased contrast in all patients (epidermal melasma). The number of sessions ranged from two to six. All 12 patients showed marked improvement, as calculated by the MASI score before and after treatment, and the response was highly statistically significant. No side effect was recorded in all treated patients.
Conclusion: Lactic acid was found to be a new effective and safe peeling agent in the treatment of melasma.