Eczema is a common skin condition marked itchy and inflamed patches of skin. It is also known as atopic dermatitis. It is more common in babies and young children. It occurs on the faces of infants, as well as inside the elbows and behind the knees of children, teenagers, and adults.czema is characterized by itchy, dry, rough, flakey, inflamed, and irritated skin. It can flare up, subside, and then flare up again. It can occur anywhere but usually affects the arm, inner elbow, back of the knee, or head (particularly the cheeks and the scalp). It is not contagious and becomes less severe with age.