Comparison between the efficacy of 10% zinc sulfate solution with 4% hydroquinone cream on improvement of melasma

Melasma, a common disorder of hyperpigmentation, is often difficult to treat. Although 10% zinc sulfate solution has been reported to be useful for patients with melasma, controlled trials are lacking.

72 women with moderate to severe melasma were divided randomly into 2 groups. Group A were treated with 10% zinc sulfate solution and group B with 4% hydroquinone cream twice-daily. The results were evaluated by photoevaluation by patients based on subjective satisfaction and a blinded dermatologist using MASI score. Assessments were obtained at baseline and at 2 and 6 months after starting treatment.

According to MASI score changes during treatment, there was a reduction in both groups at 2 months, however, the reduction in group B was more significant (the reduction in mean ± SD MASI was 0.7 ± 0.7 in group A vs. 2.7 ± 1.6 in group B). In addition, the patients in group B continued to decrease MASI score for the remainder of the study period at 6 months follow-up (0.3 ± 0.5) in comparison with patients in group A who did not show more reduction in MASI score.

The study indicates that topical zinc sulfate is not as effective in treating disease as was observed in the previous open study. A comparative study with sunscreen and placebo is necessary to determine if topical zinc sulfate is truly superior to sunscreen and placebo in this respect.