Another extremely difficult-to-treat cause of skin discoloration is post-inflammatory hyperpigmentation caused by acne, psoriasis, dermatitis, drug-induced, or some other trauma to the skin. Prescription-level (3 to 5%) topical hydroquinone twice daily may offer some lightening effect, but one study suggested that implementing a regimen of glycolic acid peels, twice daily application of a hydroquinone-glycolic acid topical combination and a retinoid like tretinoin before sleeping produced results faster.1
References:
- Plensdorf, Scott and Martinez, Joy. American Family Physician Volume 79, Issue 2: Common Pigmentation Disorders. MD Consult: American Academy of Family Physicians. [Online] January 2009. http://www.mdconsult.com/das/article/body/178618016-2/jorg=journal&source=MI&sp=21650863&sid=0/N/680808/1.html?issn=0002-838X.
