Hyperpigmentation refers to skin that has turned darker than normal where the change that has occurred is unrelated to sun exposure. Cells called melanocytes located in the skin, produce melanin. Melanin gives the skin its color. In certain conditions melanocytes can become abnormal and cause an excessive amount of darkening in the color of the skin.
Update Date 5/15/2013
Updated by: Kevin Berman, MD, PhD, Atlanta Center for Dermatologic Disease, Atlanta, GA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial Team.