Keratosis pilaris on the upper arm.
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.
Who is affected by atopic dermatitis?
Atopic dermatitis is very common. It affects males and females at about the same rate. Although atopic dermatitis may occur at any age, it most often begins in infancy and childhood. Scientists estimate that 65 percent of patients develop symptoms in the first year of life, and 85% develop symptoms before the age of 5. Onset after age 30 is less common and is often caused by exposure of the skin to harsh or wet conditions. Atopic dermatitis is a common cause of workplace disability. People who live in cities and in dry climates appear more likely to develop this condition.
It is difficult to identify exactly how many people are affected by atopic dermatitis. Many people report that they have symptoms, but never have received a diagnosis from a doctor. An estimated 10 to 20% of infants and young children experience symptoms of the disease. Roughly 60% of these infants continue to have one or more symptoms of atopic dermatitis in adulthood. In adults, the prevalence is thought to be 1 to 3%, with an overall lifetime prevalance of about 7%.
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 individuals who have inherited the atopic disease trait.
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. Scientists have found that people with atopic dermatitis have a low level of a cytokine (a protein) that is essential to the healthy function of the body's immune system and a high level of other cytokines that lead to allergic reactions. 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|
Symptoms vary from person to person. The most common symptoms are dry, itchy skin and rashes on the face, inside the elbows and behind the knees, and on the hands and feet. Itching is the most important symptom of atopic dermatitis. Scratching and rubbing in response to itching irritates the skin, increases inflammation, and actually increases itchiness. Itching is a particular problem during sleep when conscious control of scratching is lost.
The appearance of the skin that is affected by atopic dermatitis depends on the amount of scratching and the presence of secondary skin infections. The skin may be red and scaly, be thick and leathery, contain small aised bumps, or leak fluid and become crusty and infected. These features can also be found in people who do not have atopic dermatitis or who have other types of skin disorders.
Atopic dermatitis may also affect the skin around the eyes, the eyelids, and the eyebrows and lashes. Scratching and rubbing the eye area can cause the skin to redden and swell. Some people with atopic dermatitis develop an extra fold of skin under their eyes. Patchy loss of eyebrows and eyelashes may also result from scratching or rubbing.
Researchers have noted differences in the skin of people with atopic dermatitis that may contribute to the symptoms of the disease. The outer layer of skin, called the epidermis, is divided into two parts: an inner part containing moist, living cells, and an outer part, known as the horny layer or stratum corneum, containing dry, flattened, dead cells. Under normal conditions the stratum corneum acts as a barrier, keeping the rest of the skin from drying out and protecting other layers of skin from damage caused by irritants and infections. When this barrier is damaged, irritants act more intensely on the skin.
The skin of a person with atopic dermatitis loses moisture from the epidermal layer, allowing the skin to become very dry and reducing its protective abilities. Thus, when combined with the abnormal skin immune system, the person's skin is more likely to become infected by bacteria (for example, Staphylococcus and Streptococcus) or viruses, such as those that cause warts and cold sores.
Stages of atopic dermatitis
When atopic dermatitis occurs during infancy and childhood, it affects each child differently in terms of both onset and severity of symptoms. In infants, atopic dermatitis typically begins around 6 to 12 weeks of age. It may first appear around the cheeks and chin as a patchy facial rash, which can progress to red, scaling, oozing skin. The skin may become infected. Once the infant becomes more mobile and begins crawling, exposed areas, such as the inner and outer parts of the arms and legs, may also be affected. An infant with atopic dermatitis may be restless and irritable because of the itching and discomfort of the disease.
In childhood, the rash tends to occur behind the knees and inside the elbows; on the sides of the neck; around the mouth; and on the wrists, ankles, and hands. Often, the rash begins with papules that become hard and scaly when scratched. The skin around the lips may be inflamed, and constant licking of the area may lead to small, painful cracks in the skin around the mouth.
In some children, the disease goes into remission for a long time, only to come back at the onset of puberty when hormones, stress, and the use of irritating skin care products or cosmetics may cause the disease to flare.
Although a number of people who developed atopic dermatitis as children also experience symptoms as adults, it is also possible for the disease to show up first in adulthood. The pattern in adults is similar to that seen in children; that is, the disease may be widespread or limited to only a few parts of the body. For example, only the hands or feet may be affected and become dry, itchy, red, and cracked. Sleep patterns and work performance may be affected, and long-term use of medications to treat the atopic dermatitis may cause complications. Adults with atopic dermatitis also have a predisposition toward irritant contact dermatitis, where the skin becomes red and inflamed from contact with detergents, wool, friction from clothing, or other potential irritants. It is more likely to occur in occupations involving frequent hand washing or exposure to chemicals. Some people develop a rash around their nipples. These localized symptoms are difficult to treat. Because adults may also develop cataracts, the doctor may recommend regular eye exams.
|Major and minor features of atopic dermatitis|
| Major features
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.
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.
If the quantity of IgE antibodies to a food in the blood is above a certain level, it is indicative of a food allergy. If 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.
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.
Children with atopic disease tend to have a higher prevalence of food allergy than those in the general population. 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, tree nuts, shellfish, and fish. A recent analysis of a large number of studies on allergies and breastfeeding indicated that breastfeeding an infant, although preferable for many reasons, has little effect on protecting the infant from developing atopic dermatitis.
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.
Treatment is more effective when a partnership develops that includes the patient, family members, and doctor. The doctor will suggest a treatment plan based on the patient's age, symptoms, and general health. The patient or family member providing care plays a large role in the success of the treatment plan by carefully following the doctor's instructions and paying attention to what is or is not helpful. Most patients will notice improvement with proper skin care and lifestyle changes.
The doctor has two main goals in treating atopic dermatitis: healing the skin and preventing flares. These may be assisted by developing skin care routines and avoiding substances that lead to skin irritation and trigger the immune system and the itch-scratch cycle. It is important for the patient and family members to note any changes in the skin's condition in response to treatment, and to be persistent in identifying the treatment that seems to work best.
New medications known as immunomodulators have been developed that help control inflammation and reduce immune system reactions when applied to the skin. They can be used in patients older than 2 years of age and have few side effects (burning or itching the first few days of application). They not only reduce flares, but also maintain skin texture and reduce the need for long-term use of corticosteroids.
Corticosteroid creams and ointments have been used for many years to treat atopic dermatitis and other autoimmune diseases affecting the skin. Sometimes over-the-counter preparations are used, but in many cases the doctor will prescribe a stronger corticosteroid cream or ointment. When prescribing a medication, the doctor will take into account the patient's age, location of the skin to be treated, severity of the symptoms, and type of preparation (cream or ointment) that will be most effective. Sometimes the base used in certain brands of corticosteroid creams and ointments irritates the skin of a particular patient. Side effects of repeated or long-term use of topical corticosteroids can include thinning of the skin, infections, growth suppression (in children), and stretch marks on the skin.
When topical corticosteroids are not effective, the doctor may prescribe a systemic corticosteroid, which is taken by mouth or injected instead of being applied directly to the skin. Typically, these medications are used only in resistant cases and only given for short periods of time. The side effects of systemic corticosteroids can include skin damage, thinned or weakened bones, high blood pressure, high blood sugar, infections, and cataracts.
It can be dangerous to suddenly stop taking corticosteroids, so it is very important that the doctor and patient work together in changing the corticosteroid dose.
Antibiotics to treat skin infections may be applied directly to the skin in an ointment, but are usually more effective when taken by mouth. If viral or fungal infections are present, the doctor may also prescribe specific medications to treat those infections.
Certain antihistamines that cause drowsiness can reduce nighttime scratching and allow more restful sleep when taken at bedtime. This effect can be particularly helpful for patients whose nighttime scratching makes the disease worse.
In adults, drugs that suppress the immune system may be prescribed to treat severe cases of atopic dermatitis that have failed to respond to other forms of therapy. These drugs block the production of some immune cells and curb the action of others. The side effects of drugs like these can include high blood pressure, nausea, vomiting, kidney problems, headaches, tingling or numbness, and a possible increased risk of cancer and infections. There is also a risk of relapse after the drug is stopped. Because of their toxic side effects, systemic corticosteroids and immunosuppressive drugs are used only in severe cases and then for as short a period of time as possible. Patients requiring systemic corticosteroids should be referred to dermatologists or allergists specializing in the care of atopic dermatitis to help identify trigger factors and alternative therapies.
In rare cases, when home-based treatments have been unsuccessful, a patient may need a few days in the hospital for intense treatment.
Use of ultraviolet A or B light waves, alone or combined, can be an effective treatment for mild to moderate dermatitis in older children (over 12 years old) and adults. A combination of ultraviolet light therapy and a drug called psoralen can also be used in cases that are resistant to ultraviolet light alone. Possible long-term side effects of this treatment include premature skin aging and skin cancer. If the doctor thinks that phototherapy may be useful to treat the symptoms of atopic dermatitis, he or she will use the minimum exposure necessary and monitor the skin carefully.
Healing the skin and keeping it healthy are important to prevent further damage and enhance quality of life. Developing and sticking with a daily skin care routine is critical to preventing flares.
A lukewarm bath helps to cleanse and moisturize the skin without drying it excessively. Because soaps can be drying to the skin, the doctor may recommend use of a mild bar soap or nonsoap cleanser. Bath oils are not usually helpful.
After bathing, a person should air-dry the skin, or pat it dry gently (avoiding rubbing or brisk drying), and then apply a lubricant to seal in the water that has been absorbed into the skin during bathing. A lubricant increases the rate of healing and establishes a barrier against further drying and irritation. Lotions that have a high water or alcohol content evaporate more quickly, and alcohol may cause stinging. Therefore, they generally are not the best choice. Creams and ointments work better at healing the skin.
Another key to protecting and restoring the skin is taking steps to avoid repeated skin infections. Signs of skin infection include tiny pustules (pus-filled bumps), oozing cracks or sores, or crusty yellow blisters. If symptoms of a skin infection develop, the doctor should be consulted and treatment should begin as soon as possible.
Protection from allergen exposure
The doctor may suggest reducing exposure to a suspected allergen. For example, the presence of the house dust mite can be limited by encasing mattresses and pillows in special dust-proof covers, frequently washing bedding in hot water, and removing carpeting. However, there is no way to completely rid the environment of airborne allergens.
Changing the diet may not always relieve symptoms of atopic dermatitis. A change may be helpful, however, when the medical history, laboratory studies, and specific symptoms strongly suggest a food allergy. It is up to the patient and his or her family and physician to decide whether the dietary restrictions are appropriate. Unless properly monitored by a physician or dietitian, diets with many restrictions can contribute to serious nutritional problems (see nutrition), especially in children.
Atopic dermatitis and quality of life
Despite the symptoms caused by atopic dermatitis, it is possible for people with the disorder to maintain a good quality of life. The keys to quality of life lie in being well-informed; awareness of symptoms and their possible cause; and developing a partnership involving the patient or caregiving family member, medical doctor, and other health professionals. Good communication is essential.
When a child has atopic dermatitis, the entire family may be affected. It is helpful if families have additional support to help them cope with the stress and frustration associated with the disease. A child may be fussy and difficult and unable to keep from scratching and rubbing the skin. Distracting the child and providing activities that keep the hands busy are helpful but require much effort on the part of the parents or caregivers. Another issue families face is the social and emotional stress associated with changes in appearance caused by atopic dermatitis. The child may face difficulty in school or with social relationships and may need additional support and encouragement from family members.
Adults with atopic dermatitis can enhance their quality of life by caring regularly for their skin and being mindful of the effects of the disease and how to treat them. Adults should develop a skin care regimen as part of their daily routine, which can be adapted as circumstances and skin conditions change. Stress management and relaxation techniques may help decrease the likelihood of flares. Developing a network of support that includes family, friends, health professionals, and support groups or organizations can be beneficial. Chronic anxiety and depression may be relieved by short-term psychological therapy.
Recognizing the situations when scratching is most likely to occur may also help. For example, many patients find that they scratch more when they are idle, and they do better when engaged in activities that keep the hands occupied. Counseling also may be helpful to identify or change career goals if a job involves contact with irritants or involves frequent hand washing, such as work in a kitchen or auto machine shop.