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, 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 personal and family medical histories.
Treatment includes practicing general skin care, applying corticosteroids to the skin, and sometimes using other treatments such as phototherapy or immune system‒modulating drugs.
(See also Overview of Dermatitis.)
Atopic dermatitis is one of the most common skin disorders, particularly in urban areas or developed countries. Each year, up to about 10% of adults and 20% of children are diagnosed with atopic dermatitis. 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. Atopic dermatitis may begin during late adulthood or even later in life.
Atopic dermatitis is caused by a genetic defect of the skin barrier that predisposes the skin to inflammation. It often runs in families and many people or their family members who have atopic dermatitis also have asthma, hay fever, or both. Atopic dermatitis is not an allergy to a particular substance, but having atopic dermatitis increases the likelihood of also developing asthma and hay fever (what doctors call an atopic triad). Atopic dermatitis is not contagious.
Atopic dermatitis usually begins in infancy, as early as 3 months of age.
In the early (acute) phase, red, oozing, and crusted areas develop, and sometimes blisters. Itching is often intense.
In the chronic (later) phase, scratching and rubbing creates areas that appear dry and lichenified.
In infants, rashes on the face spread to the neck, eyelids, scalp, hands, arms, feet, and legs. Large areas of the body may be affected.
In older children and adults, a rash often occurs (and recurs) in only one or a few spots, especially on the front of the neck, the inner folds of the elbows, and behind the knees.
Although the color, intensity, and location of the rash vary, the rash always itches. In older children and adults, intense itching is the main symptom. The itching often leads to uncontrollable scratching, triggering a cycle of itching-scratching-itching that makes the problem worse. Continuous scratching causes the skin to thicken (lichenification).
Itching worsens with dry air, irritation, and emotional stress.
Common environmental triggers of symptoms include
Scratching and rubbing can also tear the skin, leaving an opening for bacteria to enter and cause infections of the skin, tissues below the skin, and nearby lymph nodes. Widespread inflammation and scaling of the skin also can develop.
In people with atopic dermatitis, infection with the herpes simplex virus, which in other people usually affects a small area with tiny, slightly painful blisters, may cause a serious illness with widespread dermatitis, blistering, and high fever (eczema herpeticum).
People who have atopic dermatitis also have a higher risk of allergic contact reactions. These contact reactions are triggered when the skin comes in to contact with an allergen, which is a substance that sensitizes the skin. For example, contact allergies to nickel, the most common contact allergen, are twice as common among people who have atopic dermatitis than among people who do not have atopic dermatitis.
Atopic dermatitis often lessens by the time children are 5 years of age. However, flare-ups are common throughout adolescence and into adulthood. Girls and people who developed atopic dermatitis at an early age, have a severe case, have a family history, and have rhinitis or asthma are more likely to have atopic dermatitis for a long time. Even in these people, however, atopic dermatitis frequently resolves or lessens significantly by adulthood. Because the symptoms of atopic dermatitis are visible and sometimes disabling, children may develop long-term emotional problems as they face the challenge of living with the disorder during their developmental years.
Avoiding excessive washing or bathing, reducing the use of soap, using lukewarm water when washing or bathing, and applying moisturizers very often can prevent or at least reduce flare-ups.
Identifying and avoiding triggers that worsen the condition can help. Triggers include sweat, stress, soaps, and detergents.
No cure exists, but itching can be relieved with drugs applied to the skin (topical drugs) or drugs taken by mouth. Treatments of itching can usually be given at home, but people who have erythroderma, cellulitis, or eczema herpeticum may need to be hospitalized.
Doctors educate people about good skin care practices and the importance of breaking the itch–scratch cycle.
Certain skin care measures are helpful:
Using soap substitutes instead of regular soap
Applying moisturizers (ointments or creams) immediately after bathing, while the skin is damp
Reducing the frequency of bathing (showers/baths should be limited to once a day, and sponge baths can be substituted to decrease the number of days with full baths)
Limiting the temperature of bathing water to lukewarm
Blotting or patting the skin dry after bathing rather than rubbing
Taking baths with diluted bleach for people who have certain skin infections
Antihistamines, such as hydroxyzine and diphenhydramine, can help relieve itching. These drugs are preferably taken at bedtime to avoid sleepiness during the day.
People should also try to reduce their emotional stress.
Topical corticosteroids are the mainstay of treatment. Specific treatments include applying a corticosteroid ointment or cream. To limit the use of corticosteroids in people being treated for long periods (because long-term use can lead to thinning of the skin, stretch marks, or acne-like bumps), doctors sometimes replace the corticosteroids with noncorticosteroid treatments for eczema, for a week or more at a time.
The immune system‒modulating drugs tacrolimus or pimecrolimus also are helpful and can limit the need for long-term corticosteroid use. These drugs are usually given as ointments or creams.
Crisaborole ointment can be used to reduce itching, swelling, and redness.
Phototherapy (exposure to ultraviolet light) may help, especially therapy using narrowband ultraviolet B light. If office-based phototherapy is not available or too inconvenient, home phototherapy is a good alternative. Several home phototherapy devices have programmable features that allow specialists to control the number of treatments and supervise a person's use of the device. Natural sun exposure is an alternative when phototherapy is not available.
Immunosuppressants, such as cyclosporine, mycophenolate, methotrexate, and azathioprine, are taken by mouth. They are given to people who have widespread, hard-to-treat, or disabling atopic dermatitis that does not get better with topical therapy and phototherapy.
Dupilumab is a biologic agent that is injected. It is given to people whose atopic dermatitis is not adequately controlled with other treatments.
Antibiotics may be given to people who have skin infections caused by Staphylococcus aureus or other bacteria. Antibiotic ointments may be applied directly to the skin or the drugs may be taken by mouth.
People who have the bacterium Staphylococcus aureus in their nose may be given the antibiotic mupirocin to apply inside their nostrils, thus preventing skin infection.
Parents should cut their children's fingernails short to minimize scratching and thus reduce the risk of infection. If a skin infection does occur, antibiotics may be given by mouth, applied to the skin, or both.
Eczema herpeticum is treated with the antiviral drugs, such as acyclovir or valacyclovir. These drugs are taken by mouth but can also be given by infusion.