Epidemiology

Globally eczema affected approximately 230 million people as of 2010 (3.5% of the population). The lifetime clinician-recorded prevalence of eczema has been seen to peak in infancy, with female predominance of eczema presentations occurring during the reproductive period of 15–49 years. In the UK about 20% of children have the condition, while in the United States about 10% are affected.

Although little data on the rates of eczema over time exists prior to the Second World War (1939–45), the rate of eczema has been found to have increased substantially in the latter half of the 20th Century, with eczema in school-aged children being found to increase between the late 1940s and 2000. In the developed world there has been rise in the rate of eczema over time. The incidence and lifetime prevalence of eczema in England has been seen to increase in recent times.

Dermatitis affected about 10% of U.S. workers in 2010, representing over 15 million workers with dermatitis. Prevalence rates were higher among females than among males, and among those with some college education or a college degree compared to those with a high school diploma or less. Workers employed in healthcare and social assistance industries and life, physical, and social science occupations had the highest rates of reported dermatitis. About 6% of dermatitis cases among U.S. workers were attributed to work by a healthcare professional, indicating that the prevalence rate of work-related dermatitis among workers was at least 0.6%.

Prognosis

Most cases are well managed with topical treatments and ultraviolet light. About 2% of cases however are not. In more than 60% the condition goes away by adolescence.

Management

There is no known cure for eczema, with treatment aiming to control symptoms by reducing inflammation and relieving itching.

Lifestyle

Bathing once or more a day is recommended. It is a misconception that bathing dries the skin in people with eczema. It is not clear whether dust mite reduction helps with eczema.

There has not been adequate evaluation of changing the diet to reduce eczema. There is some evidence that infants with an established egg allergy may have a reduction in symptoms if eggs are eliminated from their diets. Benefits have not been shown for other elimination diets, though the studies are small and poorly executed. Establishing that there is a food allergy before dietary change could avoid unnecessary lifestyle changes.

People can also wear clothing designed to manage the itching, scratching and peeling. Soaps and detergents should not be used on affected skin because they can strip natural skin oils and lead to excessive dryness.

Moisturizers

Moisturizing agents (also known as emollients) are recommended at least once or twice a day. Oilier formulations appear to be better and water based formulations are not recommended. It is unclear if moisturizers that contain ceramides are more or less effective than others. Products that contain dyes, perfumes, or peanuts should not be used. Occlusive dressings at night may be useful.

Medications

There is little evidence for antihistamine and they are thus not generally recommended. Sedative antihistamines, such as diphenhydramine, may be tried in those who are unable to sleep due to eczema.

Corticosteroids

If symptoms are well controlled with moisturizers, steroids may only be required when flares occur. Corticosteroids are effective in controlling and suppressing symptoms in most cases. Once daily use is generally enough. For mild-moderate eczema a weak steroid may be used (e.g. hydrocortisone), while in more severe cases a higher-potency steroid (e.g. clobetasol propionate) may be used. In severe cases, oral or injectable corticosteroids may be used. While these usually bring about rapid improvements, they have greater side effects.

Long term use of topical steroids may result in skin atrophy, stria or telangiectasia. Their use on delicate skin (face or groin) is therefore typically with caution. They are, however, generally well tolerated.

Immunosuppressants

Topical immunosuppressants like pimecrolimus and tacrolimus may be better in the short term and appear equal to steroids after a year of use. Their use is reasonable in those who do not respond to or are not tolerant of steroids. Treatments are typically recommended for short or fixed periods of time rather than indefinitely. Tacrolimus .1% has generally proved more effective than picrolimus, and equal in effect to mid-potency topical steroids.

The United States Food and Drug Administration has issued a health advisory a possible risk of lymph node or skin cancer from these products, however subsequent research has not supported these concerns. A major debate, in the UK, has been about the cost of these medications and, given only finite NHS resources, when they are most appropriate to use.

When eczema is severe and does not respond to other forms of treatment, systemic immunosuppressants are sometimes used. Immunosuppressants can cause significant side effects and some require regular blood tests. The most commonly used are ciclosporin, azathioprine and methotrexate.

Light therapy

Light therapy using ultraviolet light has tentative support but the quality of the evidence is not very good. A number of different types of light may be used including UVA and UVB. Overexposure to ultraviolet light carries its own risks, particularly that of skin cancer.

Alternative medicine

There is currently no scientific evidence for the claim that sulfur treatment relieves eczema. It is unclear whether Chinese herbs help or harm. Dietary supplements are commonly used by people with eczema. Neither evening primrose oil nor borage seed oil taken orally have been shown to be effective. Both are associated with gastrointestinal upset. Probiotics do not appear to be effective. There is insufficient evidence to support the use of zinc, selenium, vitamin D, vitamin E, pyridoxine (vitamin B6), sea buckthorn oil, hempseed oil, sunflower oil, or fish oil as dietary supplements.

Other remedies lacking evidential support include chiropractic spinal manipulation and acupuncture. There is little evidence supporting the use of psychological treatments. While dilute bleach baths have been used for infected dermatitis there is little evidence for this practice.

Prevention

There is no good evidence that a mother's diet during pregnancy, the formula used, or breastfeeding changes the risk. There is tentative evidence that probiotics in infancy may reduce rates but it is insufficient to recommend its use.

People with eczema should not get the smallpox vaccination due to risk of developing eczema vaccinatum, a potentially severe and sometimes fatal complication.

Diagnosis

Diagnosis of eczema is based mostly on the history and physical examination. However, in uncertain cases, skin biopsy may be useful. Those with eczema may be especially prone to misdiagnosis of food allergies.

Patch tests are used in the diagnosis of allergic contact dermatitis.

Cause

The cause of eczema is unknown but is presumed to be a combination of genetic and environmental factors.

Environmental

The hygiene hypothesis postulates that the cause of asthma, eczema, and other allergic diseases is an unusually clean environment. It is supported by epidemiologic studies for asthma. The hypothesis states that exposure to bacteria and other immune system modulators is important during development, and missing out on this exposure increases risk for asthma and allergy.

While it has been suggested that eczema may sometimes be an allergic reaction to the excrement from house dust mites, with up to 5% of people showing antibodies to the mites, the overall role this plays awaits further corroboration.

Genetic

A number of genes have been associated with eczema, one of which is filaggrin. Genome-wide studies found three new genetic variants associated with eczema: OVOL1, ACTL9 and IL4-KIF3A.

Eczema occurs about three times more frequently in celiac disease and about two times more frequently in relatives of those with celiac disease, potentially indicating a genetic link between the two conditions.

Signs and symptoms

Dermatitis symptoms vary with all different forms of the condition. They range from skin rashes to bumpy rashes or including blisters. Although every type of dermatitis has different symptoms, there are certain signs that are common for all of them, including redness of the skin, swelling, itching and skin lesions with sometimes oozing and scarring. Also, the area of the skin on which the symptoms appear tends to be different with every type of dermatitis, whether on the neck, wrist, forearm, thigh or ankle. Although the location may vary, the primary symptom of this condition is itchy skin. More rarely, it may appear on the genital area, such as the vulva or scrotum. Symptoms of this type of dermatitis may be very intense and may come and go. Irritant contact dermatitis is usually more painful than itchy.

Although the symptoms of atopic dermatitis vary from person to person, the most common symptoms are dry, itchy, red skin. Typical affected skin areas include the folds of the arms, the back of the knees, wrists, face and hands.

Dermatitis herpetiformis symptoms include itching, stinging and a burning sensation. Papules and vesicles are commonly present. The small red bumps experienced in this type of dermatitis are usually about 1 cm in size, red in color and may be found symmetrically grouped or distributed on the upper or lower back, buttocks, elbows, knees, neck, shoulders, and scalp. Less frequently, the rash may appear inside the mouth or near the hairline.

The symptoms of seborrheic dermatitis on the other hand, tend to appear gradually, from dry or greasy scaling of the scalp (dandruff) to hair loss. In severe cases, pimples may appear along the hairline, behind the ears, on the eyebrows, on the bridge of the nose, around the nose, on the chest, and on the upper back. In newborns, the condition causes a thick and yellowish scalp rash, often accompanied by a diaper rash.

Perioral dermatitis refers to a red bumpy rash around the mouth.