OverviewCumulative skin damage is caused by repeated exposure to the ultraviolet light found in sunshine. Areas with high exposure such as the scalp (bald individuals), forearms, face, and back of the neck are common sites. Over the years, the genetic material of cells becomes irreparably damaged and produces lesions like these on the scalp. The lesions, called actinic keratosis, may later become cancerous.
Review Date 8/20/2016
Updated by: David L. Swanson, MD, Vice Chair of Medical Dermatology, Associate Professor of Dermatology, Mayo Medical School, Scottsdale, AZ. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.