Azelaic acid is a naturally occurring saturated dicarboxylic
acid which, on topical application (usually as a 20% cream), has been shown to be effective in the treatment of comedonal
acne and inflammatory (papulopustular, nodular and nodulocystic)
acne, as well as various cutaneous hyperpigmentary disorders characterised by hyperactive/abnormal melanocyte function, including
melasma and, possibly,
lentigo maligna. In addition,
azelaic acid has an antiproliferative and cytotoxic effect on the human malignant melanocyte, and preliminary findings indicate that it may arrest the progression of
cutaneous malignant melanoma. The mechanism of this selective cytotoxic action of
azelaic acid is unclear, but may possibly be related to its inhibition of mitochondrial
oxidoreductase activity and
DNA synthesis. In controlled studies, topical
azelaic acid demonstrated comparable anti-
acne efficacy to topical
tretinoin,
benzoyl peroxide, erythromycin and oral
tetracycline, while in patients with
melasma azelaic acid proved at least as effective as topical
hydroquinone. On topical application
azelaic acid is well tolerated, with adverse effects apparently limited to a generally mild and transient local cutaneous irritation. Thus, topical
azelaic acid, employed either as monotherapy or in combination with other treatments, is likely to prove of value in the management of
acne and several hyperpigmentary disorders, most notably
melasma.