These red, scaly plaques on the legs are caused by an inherited allergic condition called atopic dermatitis. Many of these areas have been scratched until they are raw and infected, with the infection triggering and perpetuating the problem. In adults, atopic dermatitis frequently involves the body creases, such as inside the elbows and behind the knees.
Review Date 11/18/2022
Updated by: Elika Hoss, MD, Assistant Professor of Dermatology, Mayo Clinic, Scottsdale, AZ. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.