For people with actinic keratosis, cumulative skin damage is caused by repeated exposure to all ultraviolet light, including that found in sunshine. Over the years, the genetic material of cells becomes irreparably damaged and produces lesions. The lesions, like those seen here on the arm, may later become cancerous.
Kevin Berman, MD, PhD, Atlanta Center for Dermatologic Disease, Atlanta, GA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.