Background and objective Treatment of atrophic acne scars is difficult and generally unsatisfactory. Although many clinical studies have been performed to investigate the efficacy of glycolic acid in the treatment of acne vulgaris, to the best of our knowledge no placebo-controlled study has been carried out to ascertain the effect of glycolic acid on atrophic postacne scars.
Design A single, blind, placebo-controlled, randomized comparative clinical study was conducted in 58 women with atrophic acne scars. The subjects were randomly divided into three study groups. Glycolic acid peels with 20%, 35%, 50%, and 70% concentrations were applied serially at 2-week intervals to 23 patients in Group A. Twenty patients in Group B used a 15% glycolic acid cream once or twice daily for a period of 24 weeks. The remaining 15 patients in Group C applied a placebo cream twice daily during the same period.
Results The differences between the results in the different groups were statistically significant at week 24 (P < 0.001). Home application of low-strength glycolic acid was better tolerated and had less side-effects than glycolic acid peels; however, repeated short-contact 70% glycolic acid peels provided superior results compared with the maintenance regimen (P < 0.05), and apparently good responses were observed only in the peel group (P < 0.01).
Conclusions Glycolic acid peeling is an effective modality for the treatment of atrophic acne scars, but repetitive peels (at least six times) with 70% concentration are necessary to obtain evident improvement. Long-term daily use of low-strength products may also have some useful effects on scars and may be recommended for patients who cannot tolerate the peeling procedure.