Cumulative 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 11/10/2020
Updated by: Ramin Fathi, MD, FAAD, Director, Phoenix Surgical Dermatology Group, Phoenix, AZ. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.