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 10/24/2016
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.