Atopic dermatitis (AD) is the most common type of eczema, occurring in approximately six percent of the population. AD is characterized by a defect in the skin barrier, which allows allergens and other irritants to enter the skin, leading to an immune reaction and inflammation. This reaction produces a red, itchy rash, most frequently occurring on the face, arms and legs, and the rash can cover significant areas of the body, in some cases half of the body or more. The disease typically begins in early childhood and is chronic, but many sufferers outgrow it as they age, although it persists into adolescence and even adulthood in some individuals. The rash causes significant pruritus (itching), which can lead to damage caused by scratching or rubbing. Since a large percentage of AD patients are very young children, safety is a particularly important consideration in treatment selection. In 2017, according to Decision Resources, 9.8 million AD patients in the United States received prescription therapy for their disease, of which 72% received topical therapy, either alone or in combination with other treatments.