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Atopic Dermatitis or Eczema
How is Atopic Dermatitis Diagnosed?
Each person experiences a unique combination of symptoms, which may vary in severity over time. The doctor will base a diagnosis on the symptoms the patient experiences and may need to see the patient several times to make an accurate diagnosis and to rule out other diseases and conditions that might cause skin irritation. In some cases, the family doctor or pediatrician may refer the patient to a dermatologist (doctor specializing in skin disorders) or allergist (allergy specialist) for further evaluation.
A medical history may help the doctor better understand the nature of a patient's symptoms, when they occur, and their possible causes. The doctor may ask about family history of allergic disease; whether the patient also has diseases such as hay fever or asthma; and about exposure to irritants, sleep disturbances, any foods that seem to be related to skin flares, previous treatments for skin-related symptoms, and use of steroids or other medications. A preliminary diagnosis of atopic dermatitis can be made if the patient has three or more features from each of two categories: major features and minor features. Some of these features are listed in the box on page 14.
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 IgE (allergic) antibodies to the substance tested. IgE (immunoglobulin E) controls the immune system's allergic response and is often high in atopic dermatitis.
Recently, it was shown that if the quantity of IgE antibodies to a food in the blood is above a certain level, it is diagnostic of a food allergy. If the level of IgE to a specific food does not exceed the level needed for diagnosis but a food allergy is suspected, a person might be asked to record everything eaten and note any reactions. Physician-supervised food challenges (that is, the introduction of a food) following a period of food elimination may be necessary to determine if symptomatic food allergy is present. Identifying the food allergen may be difficult when a person is also being exposed to other possible allergens at the same time or symptoms may be triggered by other factors, such as infection, heat, and humidity.
Major and Minor Features of Atopic Dermatitis
Major Features
• Intense itching
• Characteristic rash in locations typical of the disease
• Chronic or repeatedly occurring symptoms
• Personal or family history of atopic disorders (eczema, hay fever, asthma)
Some Minor Features
• Early age of onset
• Dry skin that may also have patchy scales or rough bumps
• High levels of immunoglobulin E (IgE), an antibody, in the blood
• Numerous skin creases on the palms
• Hand or foot involvement
• Inflammation around the lips
• Nipple eczema
• Susceptibility to skin infection
• Positive allergy skin tests
Factors 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 substances that directly affect the skin and, when present in high enough concentrations with long enough contact, cause the skin to become red and itchy or to burn. Specific irritants affect people with atopic dermatitis to different degrees. Over time, many patients and their family members learn to identify the irritants causing the most trouble. For example, frequent wetting and drying of the skin may affect the skin barrier function. Also, wool or synthetic fibers and rough or poorly fitting clothing can rub the skin, trigger inflammation, and cause the itch-scratch cycle to begin. Soaps and detergents may have a drying effect and worsen itching, and some perfumes and cosmetics may irritate the skin. Exposure to certain substances, such as solvents, dust, or sand, may also make the condition worse. Cigarette smoke may irritate the eyelids. Because the effects of irritants vary from one person to another, each person can best determine what substances or circumstances cause the disease to flare.
Allergens are substances from foods, plants, animals, or the air that inflame the skin because the immune system overreacts to the substance. Inflammation occurs even when the person is exposed to small amounts of the substance for a limited time. Although it is known that allergens in the air, such as dust mites, pollens, molds, and dander from animal hair or skin, may worsen the symptoms of atopic dermatitis in some people, scientists aren't certain whether inhaling these allergens or their actual penetration of the skin causes the problems. When people with atopic dermatitis come into contact with an irritant or allergen they are sensitive to, inflammation-producing cells become active. These cells release chemicals that cause itching and redness. As the person responds by scratching and rubbing the skin, further damage occurs.
Common Irritants
• Wool or synthetic fibers
• Soaps and detergents
• Some perfumes and cosmetics
• Substances such as chlorine, mineral oil, or solvents
• Dust or sand
• Cigarette smoke
A number of studies have shown that foods may trigger or worsen atopic dermatitis in some people, particularly infants and children. In general, the worse the atopic dermatitis and the younger the child, the more likely food allergy is present. An allergic reaction to food can cause skin inflammation (generally an itchy red rash), gastrointestinal symptoms (abdominal pain, vomiting, diarrhea), and/or upper respiratory tract symptoms (congestion, sneezing, and wheezing). The most common allergenic (allergy-causing) foods are eggs, milk, peanuts, wheat, soy, and fish. A recent analysis of a large number of studies on allergies and breastfeeding indicated that breastfeeding an infant for at least 4 months may protect the child from developing allergies. However, some studies suggest that mothers with a family history of atopic diseases should avoid eating common allergenic foods during late pregnancy and breastfeeding.
In addition to irritants and allergens, emotional factors, skin infections, and temperature and climate play a role in atopic dermatitis. Although the disease itself is not caused by emotional factors, it can be made worse by stress, anger, and frustration. Interpersonal problems or major life changes, such as divorce, job changes, or the death of a loved one, can also make the disease worse.
Bathing without proper moisturizing afterward is a common factor that triggers a flare of atopic dermatitis. The low humidity of winter or the dry year-round climate of some geographic areas can make the disease worse, as can overheated indoor areas and long or hot baths and showers. Alternately sweating and chilling can trigger a flare in some people. Bacterial infections can also trigger or increase the severity of atopic dermatitis. If a patient experiences a sudden flare of illness, the doctor may check for infection.
What is Atopic Dermatitis?
What are the different types of Atopic Dermatitis(eczema)?
What are the causes of Atopic Dermatitis?
What are the Symptoms of Atopic Dermatitis?
How is Atopic Dermatitis treated?
