Atopic dermatitis is chronic, itchy inflammation of the upper layers of the skin that often develops in people who have hay fever or asthma and in people who have family members with these conditions.
Atopic dermatitis is very common, particularly in developed countries and among people who have a tendency to develop allergies.
Infants tend to develop red, oozing, crusted rashes on the face, scalp, diaper area, hands, arms, feet, or legs.
Older children and adults tend to develop one or a few spots, usually on the hands, upper arms, in front of the elbows, or behind the knees.
Doctors base the diagnosis on the appearance of the rash and the person's family medical history.
Treatment includes keeping the skin moist, applying corticosteroids to the skin, and sometimes other measures.
Atopic dermatitis is one of the most common skin diseases, particularly in urban areas or developed countries, affecting about 20% of children or adolescents and 1 to 3% of adults in developed countries. Most people develop the disorder before age 5, and many people develop it before age 1. Atopic dermatitis that develops during childhood frequently goes away or lessens greatly by adulthood.
Doctors do not know what causes atopic dermatitis, but it is related to genes and often runs in families along with asthma, hay fever (see Seasonal Allergies), and food allergies. The relationship between the dermatitis and these disorders is not clear because atopic dermatitis is not an allergy to a particular substance. Atopic dermatitis is not contagious.
Many conditions can make atopic dermatitis worse, including emotional stress, changes in temperature or humidity, bacterial skin infections, certain airborne particles (such as dust mites, molds, and dander), some cosmetics, and contact with irritating clothing (especially wool). In some infants, food allergies may provoke atopic dermatitis.