Atopic dermatitis is a long-term (chronic) skin disorder that involves scaly and itchy rashes.

Causes, incidence, and risk factors

Atopic dermatitis is due to a hypersensitivity reaction (similar to an allergy) in the skin, which leads to long-term swelling and redness (inflammation) of the skin. People with atopic dermititis may lack certain proteins in the skin, which leads to greater sensitivity.

Atopic dermatitis is most common in infants. It may start as early as age 2 to 6 months. Many people outgrow it by early adulthood.

People with atopic dermatitis often have asthma or seasonal allergies. There is often a family history of allergic conditions such as asthma, hay fever, or eczema. People with atopic dermatitis often test positive to allergy skin tests.

However, atopic dermatitis is not caused by allergies. The condition tends to get worse when the person is exposed to certain triggers.

The following can make atopic dermatitis symptoms worse:

• Cold and dry air in the winter
• Colds or the flu
• Contact with irritants and chemicals
• Contact with rough materials, such as wool
• Dry skin
• Emotions and stress
• Exposure to too much water, such as taking too many baths or showers and swimming too often
• Feeling too hot or too cold, as well as sudden temperature changes
• Fragrances or dyes added to skin lotions or soaps

Symptoms

Typical skin changes may include:

• Blisters with oozing and crusting
• Dry skin all over the body or areas of bumpy skin on the back of the arms and front of the thighs
• Ear discharge or bleeding
• Raw areas of the skin from scratching
• Skin coloring changes — more or less color than the normal skin tone (See: Skin abnormally dark or light)
• Skin redness or inflammation around the blisters
• Thickened or leather-like areas, called lichenification, which can occur after long-term irritation and scratching

Both the type of rash and where the rash appears can depend on the age of the patient:

• In children younger than age 2, skin lesions begin on the face, scalp, hands, and feet. They are often crusting, bubbling, or oozing rashes that itch.
• In older children and adults, the rash is more commonly seen on the inside of the knees and elbows, as well as the neck, hands, and feet.
• During a severe outbreak, rashes may occur anywhere on the body.
Itching, which is sometimes intense, almost always occurs. Itching may start even before the rash appears. Atopic dermatitis is often called the “itch that rashes” because the itching starts, and then the skin rash appears from the scratching.