Atopic dermatitis is a chronic (long-term) disease that affects the skin. It’s not contagious, so cannot be passed from one person to another.
The word “dermatitis” means inflammation of the skin. “Atopic” refers to a group of diseases in which there is often an inherited tendency to develop other allergic conditions, such as asthma and hay fever. In atopic dermatitis, the skin becomes extremely itchy. Scratching leads to redness, swelling, cracking, “weeping” clear fluid, and finally, crusting and scaling.
The most common symptoms of atopic dermatitis are:
- Dry and itchy skin
- Rashes on the face, inside the elbows, behind the knees, and on the hands and feet.
Scratching the skin can cause:
- “Weeping” clear fluid
- Thick skin
Often, the skin gets worse (flares), then it improves or clears up (remissions).
Who gets atopic dermatitis?
Atopic dermatitis is most common in babies and children, but it can happen to anyone. People who live in cities and dry climates may be more likely to suffer from this kind of skin problem.
In most cases, there are periods of time when the disease is worse (called exacerbations or flares) followed by periods when the skin improves or clears up entirely (called remissions). As some children with atopic dermatitis grow older, their skin disease improves or disappears altogether, although their skin often remains dry and easily irritated. In others, atopic dermatitis continues to be a significant problem in adulthood.
You can’t “catch” the disease or give it to other people.
Other types of eczema skin problems
Atopic dermatitis is often referred to as “eczema,” which is a general term for the several types of inflammation of the skin. Atopic dermatitis is the most common of the many types of eczema. Several have very similar symptoms.
- Allergic contact eczema. The skin gets red, itchy, and weepy because it touches something that the immune system knows is foreign, like poison ivy.
- Contact eczema. The skin has redness, itching, and burning in one spot because it has touched something allergy-causing, like an acid, cleaner, or other chemical.
- Dyshidrotic eczema. The skin on the palms of hands and soles of the feet is irritated and has clear, deep blisters that itch and burn.
- Neurodermatitis. Scaly patches on the head, lower legs, wrists, or forearms are caused by a localized itch (such as an insect bite).
- Nummular eczema. The skin has coin-shaped spots of irritation. The spots can be crusted, scaling, and very itchy.
- Seborrheic eczema. This skin has yellowish, oily, scaly patches on the scalp, face, and sometimes other parts of the body.
- Stasis dermatitis. The skin is irritated on the lower legs, most often from a blood flow problem.
What causes atopic dermatitis, or eczema?
The cause of atopic dermatitis is not known, but the disease seems to result from a combination of genetic (hereditary) and environmental factors.
Children are more likely to develop this disorder if a parent has had it or another atopic disease like asthma or hay fever. If both parents have an atopic disease, the likelihood increases. Although some people outgrow skin symptoms, approximately half of children with atopic dermatitis go on to develop hay fever or asthma. Environmental factors can bring on symptoms of atopic dermatitis at any time in affected individuals.
Atopic dermatitis is also associated with malfunction of the body’s immune system: the system that recognizes and helps fight bacteria and viruses that invade the body. The immune system can become misguided and create inflammation in the skin, even in the absence of a major infection. This can be viewed as a form of autoimmunity, where a body reacts against its own tissues.
In the past, doctors thought that atopic dermatitis was caused by an emotional disorder. We now know that emotional factors, such as stress, can make the condition worse, but they do not cause the disease.
Skin features associated with atopic dermatitis
- Atopic pleat (Dennie-Morgan fold): an extra fold of skin that develops under the eye
- Cheilitis: inflammation of the skin on and around the lips
- Hyperlinear palms: increased number of skin creases on the palms
- Hyperpigmented eyelids: eyelids that have become darker in color from inflammation or hay fever
- Ichthyosis: dry, rectangular scales on the skin
- Keratosis pilaris: small, rough bumps, generally on the face, upper arms, and thighs
- Lichenification: thick, leathery skin resulting from constant scratching and rubbing
- Papules: small raised bumps that may open when scratched and become crusty and infected
- Urticaria: hives (red, raised bumps) that may occur after exposure to an allergen, at the beginning of flares, or after exercise or a hot bath.
How is atopic dermatitis diagnosed?
Diagnosis is based on the symptoms. Each person has his or her own mix of symptoms that can change over time. Doctors will ask for a medical history to:
- Learn about your symptoms
- Know when symptoms occur
- Rule out other diseases
- Look for causes of symptoms.
Doctors also may ask about:
- Other family members with allergies
- Whether you have conditions such as hay fever or asthma
- Whether you have been around something that might bother the skin
- Sleep problems
- Foods that may lead to skin flares
- Treatments you have had for other skin problems
- Use of steroids or medicine.
Currently, there is no single test to diagnose atopic dermatitis. However, there are some tests that can give the doctor an indication of allergic sensitivity.
Pricking the skin with a needle that contains a small amount of a suspected allergen may be helpful in identifying factors that trigger flares of atopic dermatitis.
Negative results on skin tests may help rule out the possibility that certain substances cause skin inflammation.
Positive skin prick test results are difficult to interpret in people with atopic dermatitis, because the skin is very sensitive to many substances, and there can be many positive test sites that are not meaningful to a person’s disease at the time. Positive results simply indicate that the individual has immunoglobulin E or IgE (allergic) antibodies to the substance tested. IgE controls the immune system’s allergic response and is often high in atopic dermatitis.
Things that make atopic dermatitis worse
Many factors or conditions can make symptoms of atopic dermatitis worse, further triggering the already overactive immune system, aggravating the itch-scratch cycle, and increasing damage to the skin. These factors can be broken down into two main categories: irritants and allergens. (Emotional factors and some infections and illnesses can also influence atopic dermatitis.)
Irritants are things that may cause the skin to be red and itchy or to burn. They include:
- Wool or man-made fibers
- Soaps and cleaners
- Some perfumes and makeup
- Substances such as chlorine, mineral oil, or solvents
- Dust or sand
- Cigarette smoke.
Allergens are allergy-causing substances from foods, plants, animals, or the air. Common allergens are:
- Eggs, peanuts, milk, fish, soy products, and wheat
- Dust mites
- Dog or cat dander.
Stress, anger, and frustration can make atopic dermatitis worse, but they haven’t been shown to cause it. Skin infections, temperature, and climate can also lead to skin flares. Other things that can lead to flares are:
- Not using enough lubricants after a bath
- Low humidity in winter
- Dry year-round climate
- Long or hot baths and showers
- Going from sweating to being chilled
- Bacterial infections.