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The term eczema is derived from the Greek, meaning "to boil out." The name is particularly apt since to ancient medical practitioners it may have appeared that the skin was "boiling." Today the usage is rather imprecise since it is frequently used to describe any sort of dermatitis (inflammatory skin conditions). Not all dermatitis is eczematous. All eczematous dermatitis has a similar appearance. Acute lesions are composed of many small fluid-filled structures called vesicles that usually reside on red, swollen skin. When these structures break, the fluid leaks out, causing characteristic weeping and oozing. When the fluid dries, it produces a thin crust. In older lesions, these vesicles may be harder to appreciate, but an examination of the tissue under the microscope will reveal their presence. Eczematous dermatitis has many causes. One of the most common is a condition called atopic dermatitis. Often those using the term eczema are referring to atopic dermatitis. Although atopy refers to a lifelong. inherited (genetic) predisposition to inhalant allergies such as asthma and allergic rhinitis (hay fever), atopic dermatitis is not an allergic disease. Atopic patients are likely to have asthma, hay fever, and dermatitis. Atopy is a very common condition, and it affects all races and ages, including young infants. About 1%-2% of adults have the skin rash, and it is even more common in children. Most affected individuals have their first episode before 5 years of age. For most, the disease will improve with time. For an unlucky few, atopic dermatitis is a chronic, recurrent disorder.
Other eczematous dermatoses include, but are not limited to, allergic contact dermatitis (cell-mediated allergy to a common substance such as poison oak or nickel), irritant dermatitis (from excessive contact with a chemical substance), fungal infections, scabies infestations, stasis dermatitis, asteatosis, pompholyx (dyshidrosis), nummular dermatitis, and seborrheic dermatitis. The differentiation among these conditions is often difficult and time-consuming. In addition, it is not uncommon for atopic dermatitis to coexist with another eczematous dermatitis.
It is generally agreed that the tendency to atopy is genetically inherited. People with eczematous dermatitis have a variety of abnormal immunologic findings which are probably related to more than one genetic defect. For example, such individuals tend to have elevated IgE antibody (immunoglobulin E) levels and have difficulty in fighting off certain viral, bacterial, and fungal infections.
Like most other noninfectious diseases, atopic skin disease can be triggered by environmental factors.
Medical professionals sometimes refer to eczema as "the itch that rashes."
If twice daily applications of 1% hydrocortisone cream (available without a prescription) are insufficient to control the rash, then you should see your physician.
If you are so uncomfortable that your sleep, work, or other daily activities are disrupted, you need a more effective treatment and should see your health-care provider.
Generally, eczematous dermatitis is not an emergency and should not be handled in a hospital emergency department. Exceptions include the following:
A medical professional can usually identify the type of eczematous dermatitis by looking at the rash and asking questions about how it appeared. Samples of scale from the rash may need to be examined microscopically to search for a fungus. Occasionally, a portion of skin may be removed (a biopsy) to be examined by a pathologist.
The three key elements in identifying atopic dermatitis are
Removing whatever is causing the allergic reaction is the easiest and most effective treatment. This may be as simple as changing your laundry detergent or as difficult as moving to a new climate or changing jobs.
Prevent dry skin by taking warm (not hot) showers or baths. Use a mild soap or body cleanser. Prior to drying off, apply an effective emollient to your wet skin.. Emollients are substances that inhibit the evaporation of water. Generally, they are available in jars and have a "stiff" consistency. They do not flow and ought to leave a shine with a slightly greasy feel on the skin. Most good emollients contain petroleum jelly although certain solid vegetable shortenings do a more than creditable job.
Avoid wearing tight-fitting, rough, or scratchy clothing.
Avoid scratching the rash. If you can't stop yourself from scratching, cover the area with a dressing. Wear gloves at night to minimize skin damage from scratching.
Anything that causes sweating can irritate the rash. Avoid strenuous exercise during a flare.
An anti-inflammatory topical agent may be necessary to control a flare of atopic dermatitis.
Avoid physical and mental stress. Eating right, light activity, and adequate sleep will help you stay healthy, which can help prevent flares.
Do not expect a quick response. Atopic dermatitis is controllable but consistency in application of treatment products is necessary.
Once your health-care provider is sure you have atopic dermatitis, the mainstays of therapy are anti-inflammatory medications and relief from the itching.
Prescription-strength steroid cream and antihistamine medications are the usual treatments.
If your health-care provider determines that you have a secondary bacterial infection complicating your rash, an oral antibiotic may be prescribed.
For severe cases not responding to high-potency steroid cream, alternate treatments may be tried. These include coal tar, PUVA (psoralen + ultraviolet A light), and chemotherapeutic agents.
Allergy shots (immunotherapy) usually do not work in eczema.
Avoid, when possible, whatever triggers your rash.
See Self-Care at Home for other ideas on preventing eczema flares.
Atopic dermatitis spontaneously improves in most individuals after puberty. In a few unfortunate individuals, it becomes chronic, resulting in occasional flares of the symptoms, often at times of very low humidity (such as winter time with the heat on).
The role of psychological stress inducing flares of the dermatitis is poorly understood. There is no question that when the condition flares and sleep is inhibited by itching, one's normal ability to deal with emotional problems is diminished.
Repeated scratching of the rash can cause toughening of the skin. Small patches of the skin can become thickened and like leather. This condition is called lichen simplex chronicus.
Eczema causes skin sores and cracks that are susceptible to infection. These infections are usually very minor, but they do require treatment with antibiotics or they may become very severe. See your health-care provider if you suspect that your skin has become infected.
Eczema may fade in adulthood, but people who have eczema tend to have lifelong problems with skin irritation and related problems.
People who have eczema also tend to have more problems with family and social relationships and work difficulties.
For information about support groups, contact the following:
American Academy of Allergy, Asthma and Immunology
American Academy of Dermatology
National Eczema Association for Science and Education
Asthma and Allergy Foundation of America. "Atopic Dermatitis (Eczema)."
International Eczema-Psoriasis Foundation. "Atopic Dermatitis."
eczema, atopic dermatitis, contact dermatitis, lichen simplex chronicus, nummular dermatitis, seborrheic dermatitis
Author: Gary W. Cole, MD, FAAD
Editor: Melissa Conrad Stöppler, MD, Chief Medical Editor, eMedicineHealth.com
Previous contributing author and editors:
Author: Peter B Mishky, MD, Consulting Staff, Department of Emergency Medicine, Naval Medical Center at San Diego and Paradise Valley Hospital.
Editors: Scott H Plantz, MD, FAAEM, Research Director, Assistant Professor, Department of Emergency Medicine, Mount Sinai School of Medicine; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; James S Cohen, MD, Consulting Staff, James Cohen, PC.
REFERENCE:
Wasserbauer, N., and M. Ballow. "Atopic Dermatitis." Am J Med. 122.2 Feb. 2009: 121-125.
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