Azelaic Acid
Azelaic acid is used to treat acne as well as PIH. Available by prescription only, azelaic acid works by decreasing inflammation and speeding up cell turnover rates. Some studies have shown azelaic acid to be as effective as hydroquinone at treating hyperpigmentation. It is a good alternative for those who may be unable to use hydroquinone.
Azelaic acid is available in cream and gel form, and is sometimes used in conjunction with glycolic acid or tretinoin. As always, monitor your skin for redness and irritation and let your doctor know right away if you experience these side effects.
Procedural Treatments
More persistent cases of post inflammatory hyperpigmentation can be treated professionally at skin spas, medi-spas, or your dermatologist's office. Procedural treatments include various chemical peels and microdermabrasion. A series of treatments is needed to adequately fade PIH. Your doctor can help determine which of these treatments, if any, would be right for you.
Sources:
Cayce KA, Feldman SR, McMichael AJ. "Hyperpigmentation: a review of common treatment options." Journal of Drugs in Dermatology (2004); 3(6):668-73.
Halder RM, Richards GM. "Topical agents used in the management of hyperpigmentation." Skin Therapy Letter (2004); 9(6):1-3.
Palumbo A, dIschia M, Misuraca G, Prota G. "Mechanism of inhibition of melanogenesis by hydroquinone." Biochem Biophys Acta (1991); 1073(1):85-90.
"Skin of Color." American Academy of Dermatology. 2006. 19 Jul 2007. www.aad.org.
Kimball AB, Bissett DL, Robinson LR. "Topical formulation containing N-acetyl glucosamine and niacinamide reduces the appearance of hyperpigmented spots on human facial skin." Presented at: the 64th Annual Meeting of the American Academy of Dermatology, San Francisco, CA; March 3-7, 2006.

