Keloids are overgrowths of scar tissue that follow skin injuries. Keloids may appear after such minor trauma as ear piercing. Dark-skinned individuals tend to form keloids more readily than lighter skinned individuals. These patches of keloid have become darkly pigmented. Update Date: 05/03/2007Robert A. Cowles, MD, Assistant Professor of Surgery, Columbia University College of Physicians and Surgeons, New York, NY. Review provided by VeriMed Healthcare Network.