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The term eczema is derived from 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 this term is frequently used to describe any sort of dermatitis (an inflammatory skin condition). But not all dermatitis is eczematous. All eczematous dermatitis, whether due to familial atopic dermatitis or acquired allergic contact 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 vesicles break, clear or yellowish fluid leaks out, causing characteristic weeping and oozing. When the fluid dries, it produces a thin crust that may mimic impetigo. 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 known at this time to be a pure 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 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, dermatitis 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 harsh chemical substance), fungal infections (ringworm), scabies infestations, stasis dermatitis, very dry skin (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 inherited. For the purposes of this discussion, the term eczema and atopic dermatitis will be synonymous. Individuals with atopic dermatitis have a variety of abnormal immunologic findings, like elevated IgE antibody (immunoglobulin E) levels and defective cell-mediated immunity, which causes difficulty in fighting off certain viral, bacterial, and fungal infections. Despite a susceptibility to certain infections, eczema is not itself contagious in any way.
Like most other noninfectious diseases, atopic skin disease can be triggered by environmental factors. One of the hallmarks of atopic dermatitis is excessive skin dryness, which seems to be due a lack of certain skin proteins called filaggrins. Any factor that promotes dryness is likely to worsen atopic dermatitis. A very dry sleeping environment may be improved with a bedroom or house humidifier.
Common triggers of atopic dermatitis include the following:
Medical professionals sometimes refer to eczema as "the itch that rashes."
If twice daily applications of 0.5% or 1% hydrocortisone cream (available without a prescription) are insufficient to control the rash, then the individual should see a physician.
If someone is so uncomfortable that his/her sleep, work, or other daily activities are disrupted, he/she needs a more effective treatment and should see a health care professional.
Generally, eczematous dermatitis is not an emergency and should not be handled in a hospital emergency department. Exceptions include the following:
Most eczema can be managed by primary care physicians (family practice, pediatrics, or internal-medicine doctors). Dermatologists may be consulted when either the diagnosis is in doubt, patients are not responding to treatments that should be working, or higher-risk medications and long-term systemic medications may be needed to get adequate control of the disease.
When seeing a physician, it is important that the doctor know of everything (prescription and over-the-counter drugs, and home remedies) that the patient has tried and which things helped and which did not. As it is normal for eczema to come and go depending upon many factors, a photo taken to show things at their best or worst may also be useful to the physician.
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 (ringworm). Occasionally, a portion of skin may be removed (a biopsy) to be examined by a pathologist, but this will not distinguish atopic dermatitis from allergic contact dermatitis. A baby with what appears to be eczema of the palms and soles may have scabies, which may be confirmed with a skin scraping.
Psoriasis will lead to scaly skin but only rarely shows the weeping commonly seen with eczema. Psoriasis also doesn't itch much if at all, and eczema seldom involves the scalp while psoriasis and seborrheic dermatitis often do. While it is possible to have more than one chronic skin condition at a time, it would be unusual to have very active psoriasis and very active atopic dermatitis in the same patient at the same time.
On lighter skin, active eczema is usually red and can leave discoloration as it improves. On dark skin, there may be a mixture of light and dark color changes to the skin during and after a flare. Not enough color (hypopigmentation) is common, but total lack of color (depigmentation) should suggest other conditions, such as vitiligo or discoid lupus.
The three key elements in identifying atopic dermatitis are
Treatment for eczema can be managed at home by changing laundry detergents or soaps that may be causing the irritant. Avoid tight-fitting or rough clothing. Avoid scratching the affected area. Medical treatment includes prescription anti-inflammatory medications, and steroid creams. Antibiotics may have to be prescribed to clear the affected irritation. Anti-itch creams, especially those containing hydrocortisone, may be helpful, but many experts recommend avoiding topical diphenhydramine and topical anesthetics because of concern of becoming sensitized and developing a secondary allergic contact dermatitis in reaction to these medications. Anti-itch creams containing pramoxine and menthol may be safer in this regard.
Removing exacerbating factors is a good place to start. This may be as simple as changing the laundry detergent to one that is fragrance free or as difficult as moving to a new climate or changing jobs.
Long baths in soapy water or long hot showers may worsen eczema. On the other hand, soaking in warm, non-soapy water followed immediately by moisturizers to "seal in the moisture" is helpful. Prevent dry skin by taking short lukewarm showers or baths. Use a mild soap or body cleanser. Short contact of the skin with a shampoo is generally not a problem, but prolonged contact may worsen the rash on the neck and face. Prior to drying off, apply an effective emollient to 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. The thicker, the better, although patient preference is usually toward thinner lotions because of ease of application and avoidance of a greasy feel. Oatmeal baths (Aveeno and others) may be soothing to itchy, fissured skin although best outcomes will still result from applying moisturizers after rinsing off.
People with longstanding eczema may become sensitized to the products they are putting on the skin and develop allergic contact dermatitis that may be identical in clinical appearance. Skin allergy may develop to over-the-counter (OTC) products such as topical anesthetics, topical diphenhydramine (Benadryl), lanolin (an ingredient in Eucerin and other common moisturizers), coconut oil, and tea tree oil or even prescription medications such as topical steroid creams.
Avoid wearing tight-fitting, rough, or scratchy clothing.
Avoid scratching the rash. If it's not possible to stop 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 cream may be necessary to control a flare of atopic dermatitis.
Avoid physical and mental stress. Eating right, light activity, and adequate sleep will help someone stay healthy, which can help prevent flares.
A variety of home remedies such as apple cider vinegar and tea tree oil are frequently touted as cures for eczema, but there is little or no scientific basis for these claims. Bleach baths, on the other hand, may help. The goal of bleach baths is to suppress colonization by Staphylococcus aureus bacteria with the resulting flare that may cause. Several formulas exist, but a ½ cup of bleach for a full bathtub full of water (or ¼ cup for a half bath) is a good balance between getting the desired effect and generating an irritant dermatitis. A summer substitution for bleach baths would be regular use of overchlorinated community swimming pools.
Do not expect a quick response. Atopic dermatitis is controllable but consistency in application of treatment products is necessary.
Once a health care professional is sure someone has 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. The topical calcineurin inhibitor pimecrolimus cream (Elidel) treats mild to moderate eczema and tacrolimus ointment (Protopic) treats moderate to severe eczema. An injectable biologic (monoclonal antibody) called dupilumab (Dupixent) treats severe cases of eczema that haven't responded to other treatments.
If a health care professional determines that someone has a secondary bacterial infection complicating their 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, ultraviolet light exposure, and systemic anti-inflammatory agents.
Allergy shots (immunotherapy) usually do not work in eczema.
A variety of diets have been proposed for eczema relief. These may be structured on the results of allergy testing or may be chosen for their content of foods that tend not to provoke allergic responses. Not everyone put on restrictive eczema diets improves, and many patients with severe eczema show no testing evidence of food allergies. For that reason, a change in diet, if desired, should be considered as an additional step in treatment rather than a primary one, and if patients notice they itch more when eating any identified food or drink, it would be best if they avoid it.
Atopic dermatitis usually spontaneously improves in most individuals after puberty. In a few unfortunate individuals, it becomes chronic, resulting in occasional flares often at times of very low humidity (such as wintertime with the heat on). It may also return much later in adulthood and may prove especially difficult to manage.
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. The scrotum and vulva are common areas for adult patients with a history of eczema to develop a persistent itch and develop such lichenification. (It would be very unusual for the penis itself to be involved in such cases and other diagnoses should be considered if it appears to be affected.)
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 a health care professional if an infection is suspected.
Eczema may fade in adulthood, but people who have eczema tend to have lifelong problems with skin irritation and related problems.
Avoid, when possible, whatever triggers the rash.
See home remedies for other ideas on preventing eczema flares.
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"
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Think you know everything about eczema? Find out how much your really know about eczema by taking our atopic eczema quiz.