Background  Melasma is a common disorder of pigmentation characterized by relatively symmetric, brown or gray–brown patches on sun-exposed facial areas. Hydroquinone, the most effective agent in melasma, is known to irritate the skin, and so new alternatives in the treatment of melasma are required. We sought to assess the clinical response of a new depigmenting agent in melasma.

Methods  Ninety-six Mexican female patients with melasma were enrolled in this open, comparative, 12-week study. The patients received 1% dioic acid cream (twice daily) or 2% hydroquinone cream (twice daily).

Results  There was a significant difference in the Melasma Area Severity Index (MASI) scores from baseline to the end of the study using treatment with dioic acid (baseline, 14.52 3.4; after 12 weeks of treatment, 6.05 ± 1.2; P = 0.001) and hydroquinone (baseline, 15.22 ± 2.4; after 12 weeks of treatment, 6.34 ± 1.3; P = 0.001); however, there were no significant differences between treatments (baseline, P = 0.311; after 12 weeks of treatment, P = 0.287). The side-effects were similar with both medications; however, pruritus was more common in patients using hydroquinone.

Conclusions  Dioic acid is an effective and highly tolerated skin product, although further controlled, blind, multicenter studies are required to support these results.