Atopic dermatitis is a skin condition and type of eczema that has allergy as a major contributor. Atopic dermatitis is seen almost exclusively in infants and young children. Anywhere from 1-3 percent of children are affected. Of those, almost 85 percent will have signs and symptoms of the disease in the first year of life. The good news is that more than half will resolve the condition by the age of two. The remainder may see the end of the condition during the teenage years; a few will persist into adulthood.
The Greek term “atopic” means out of place. This is a disorder that does not seem to follow the rules of a typical allergy. The disorder usually takes about three months to develop. It is best described as an itch that rashes rather than a rash that itches. If we can stop the child from scratching the skin, the classic features of this condition do not appear. Children with atopic dermatitis are miserable, uncomfortable and, because of constant scratching, often replace the pain of itchy skin with the pain of torn skin. The constant scratching causes breakdown of the skin layer and secondary skin infections. When the body tries to repair the area, it becomes thick and leathery.
Atopic dermatitis is triggered by a number of causes, including dryness, irritants like wool and possibly allergens. Allergists have also found associations between atopic dermatitis and foods. These foods include egg, wheat, soy, cow's milk, peanut and fish.
The classic feature of atopic dermatitis is itchy skin. The skin becomes dry, flaky, rough and can become infected and show oozing and crusts.
Different areas of the body are affected at different ages. In infants, atopic dermatitis occurs on the face, cheeks, back of the arms and front of the legs. In children, the typically affected areas include the inner folds of the arms at the elbows and behind the knees. Teenagers and adults may have rash on the hands, feet and back of the neck.
The following criteria have been established for the diagnosis of atopic dermatitis.
Features that must be present include:
- Typical distribution and look of rash
- Rash on the face and back of arms for infants
- Rash in the folds of the arms and backs of knees in older children
- A tendency to be chronic, but with good days and miserable days
Two or more of the following must also be present:
- Personal or family history of allergy
- Immediate skin test reactivity (a positive test for allergy)
- A skin finding called white dermatographism (a form of hives that appear when the skin is touched)
Diagnosis can also be made when the patient presents with four or more of the following:
- Dry skin, flaky skin and hyperlinear palms (an extra number of skin creases on the palms)
- A condition called pityriasis alba (light colored patches of skin on the face)
- Keratosis pilaris (where the skin always looks like goose bumps)
- Facial pallor (the child looks pale)
- A skin fold or wrinkle under the eye called a Dennie-Morgan line
- An elevated serum IgE (found with a blood test)
- A tendency to have non-specific hand dermatitis
- A tendency to have repeated skin infections
A diagnosis is made from a combination of clinical and lab data. There is no one marker to indicate atopic dermatitis; however, 85 percent of suspected patients have elevated IgE and 85 percent have a positive skin test to egg.
As always, a physical exam and patient history are the most important elements for making a diagnosis. Parents answer questions about their child’s exposure and provide a detailed dietary history. Frequently in atopic dermatitis, there is no apparent cause-effect relationship observed by parents; however, we ask what parents think are triggers for scratching of the skin.
Allergy skin tests focus on six foods—egg, wheat, soy, cow's milk, peanut and fish—that have been established as contributing to as much as 95 percent of cases. Sometimes there may be an airborne allergen (like pollen or spores) that needs to be identified. Remember, for infants and children it takes time to develop symptoms from airborne allergens. Depending on where you live, pollen sensitization takes two to three years. Testing for animal allergy and house dust mites can be done if the history indicates those may be contributors. The flaky skin associated with atopic dermatitis helps feed the house dust mite. Inhaling an allergen may also cause flaring of the skin condition.
Treatment programs are developed for each patient, but a typical program may look like this:
- Avoidance: If there are positive food tests, strict avoidance may help. The family is given lists of each food and information on how to read labels to identify the various other names for the offending food. If an airborne allergen is identified, information for how to avoid the allergen is provided. Avoidance is always the most important therapy for the allergic child.
- Antihistamines: Histamine released by the cells of the patient will lead to itching. If a patient itches, he or she will scratch, which leads to a flare. Most itching occurs at night. Using an antihistamine on a regular basis will block the histamine response. While there are non-sedating antihistamines, children with this condition need sedation. Antihistamines do very little to stop itching. Their main use is to provide sleep, which is why they are prescribed for use at night. Non-sedating antihistamines do not offer this effect or benefit.
- Bathing: Bathing twice a day with tepid water, using Dove®, Tone® or Neutrogena® bar unscented soaps, may help. Let soak for twenty minutes and then pat dry. Do not stimulate the skin with excessive drying. Leave the skin moist. The moisture is sealed into the skin with an emollient (balm). Frequent bathing is good for this condition and moisturizes the skin.
- Ointments/creams: An ointment may be prescribed. They are heavier and greasier than creams, but penetrate better. The greasiness of the ointment helps seal the skin. Topical steroid ointments may be used. Care must be taken in applying some of these to the face, armpit and groin areas. Creams are less effective and their benefit is very brief.
- Moisturizer: Using a moisturizer, either water or oil based, that can be tolerated by the child may keep the skin moist.
- Other treatments: Avoid wool and dryness.
- Newer therapies: There are some recently FDA-approved skin applications that may have potential to treat this disorder.
Facts About Atopic Dermatitis
Some children with this disorder face quality of life issues:
- 35 percent have school problems.
- 30-50 percent may go on to develop asthma or hay fever. Unfortunately, there is no way to determine which patients will or will not develop those conditions.
- Varicella or chickenpox may be severe in this population.
- This condition will not respond to allergy shots. Frequently, those who have atopic dermatitis and asthma or allergic rhinitis and are on immunotherapy may experience worsening of the skin condition. There are reports of this complication in the medical literature and the individual response may vary.