Topical Agents Used in the Management of Hyperpigmentation

R. M. Halder, MD; G. M. Richards, MD


Skin Therapy Letter. 2004;9(6) 

In This Article

Azelaic Acid

Azelaic acid is a naturally occurring non-phenolic, saturated, nine-carbon dicarboxylic acid. Its use originated from the finding that Pityrosporum species can oxidize unsaturated fatty acids to dicarboxylic acids, which competitively inhibit tyrosinase. Azelaic acid was initially developed as a topical drug with therapeutic effects for the treatment of acne. However, because of its effect on tyrosinase, it has also been used to treat melasma, lentigo maligna and other disorders of hyperpigmention.[2,6] Azelaic acid has been reported to be effective for hypermelanosis caused by physical or photochemical agents, and lentigo maligna melanoma as well as other disorders characterized by abnormal proliferation of melanocytes. Its mechanism of action is to inhibit DNA synthesis and mitochondrial enzymes, thereby inducing direct cytotoxic effects toward the melanocyte.[6] Topical azelaic acid has no depigmentation effect on normally pigmented skin, freckles, senile lentigines, and nevi. This specificity may be attributed to its selective effects on abnormal melanocytes.

Azelaic acid can be used for postinflammatory hyperpigmentation in acne.[7] Free radicals are believed to contribute to hyperpigmentation, and azelaic acid acts by reducing free radical production.[8] Azelaic acid 20% is currently available in the US and is only indicated for the treatment of acne, although it has off-label use for hyperpigmentation. In the treatment of melasma, a 24-week study in South America found that a 20% concentration of azelaic acid was equivalent to 2% hydroquinone.[9] In the Philippines, a study found that 20% azelaic acid was better than 2% hydroquinone.[10]


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