Comparative study of therapeutic effects of 20% azelaic acid and hydroquinone 4% cream in the treatment of melasma

BACKGROUND: Melasma is an irregular brown or grayish-brown symmetric facial hypermelanosis, often affecting women, especially those living in areas with intense ultraviolet radiation. OBJECTIVE: Comparison of therapeutic effects of 20% azelaic acid and 4% hydroquinone cream in the treatment of melasma. METHODS: Twenty-nine women with melasma were recruited. Fifteen patients were treated with 4% hydroquinone cream and 14 patients were treated with azelaic acid cream for 2 months. The cream was applied twice daily. A broad-spectrum sunscreen was used concomitantly by both groups. The Melasma Area Severity Index (MASI) scores were determined prior to treatment and at each follow-up. RESULTS: The mean MASI score before treatment was 7.2 ± 3.2 in the hydroquinone group and 7.6 ± 3.5 in the azelaic acid group, with no significant difference between them (t-test, CI 95% = -2.9 to 2.2). One month after treatment, the mean MASI score reached 6.7 ± 3.4 with hydroquinone and 6.3 ± 3.4 with azelaic acid with no significant difference between them (t-test, CI 95% = -2.2 to 3). After 2 months' treatment, the MASI score was 6.2 ± 3.6 with hydroquinone and 3.8 ± 2.8 with azelaic acid, a significant statistical difference (t-test, CI 95% = 0.03-4.9). CONCLUSIONS: In conclusion, this study suggests that 20% azelaic acid cream applied twice daily may be more effective than hydroquinone 4% in reducing mild melasma. However, because this was an open trial, it is suggested that further studies involving large groups of patients be conducted to achieve a more conclusive result.