Specific dermatitis (eczema)

Atopic dermatitis is a chronic itchy inflammation of the upper skin, which often occurs in people with hay fever or asthma and family members with these diseases.

Atopic dermatitis is very common, especially in developed countries and people with allergic tendencies.

* Babies are prone to redness, exudation and rash on the face, scalp, diaper area, hands, arms, feet or legs.

* Older children and adults tend to develop one or more points, usually on the hands, upper arms, before elbows or behind knees.

* The doctor makes a diagnosis according to the appearance of the rash and the patient's family history.

* Treatment includes keeping the skin moist, using corticosteroids on the skin, and sometimes taking other measures.

Atopic dermatitis is one of the most common skin diseases, especially in urban areas or developed countries, affecting about 20% children or adolescents and 1% to 3% adults in developed countries. Most people get this disease before they are five years old, and many people get this disease before 1 year old. Atopic dermatitis that occurs in childhood often disappears or lessens in adulthood.

Doctors don't know the cause of atopic dermatitis, but it is related to genes. Asthma, hay fever (see seasonal allergy) and food allergy are often accompanied in the family. The relationship between dermatitis and these diseases is not clear, because atopic dermatitis is not an allergy to specific substances. Atopic dermatitis is not contagious.

Many conditions can worsen atopic dermatitis, including emotional stress, temperature or humidity changes, bacterial skin infections, some airborne particles (such as dust mites, molds and dander), some cosmetics and contact with irritating clothing (especially wool). In some infants, food allergy may lead to atopic dermatitis.

In the early (acute) stage, babies (usually less than 4 months old) will spread to the neck, scalp, hands, arms, feet and legs of the face, forming a red, oozing and scabby rash. Most areas of the body may be affected. This phase lasts 1 to 2 months.

In the chronic (advanced) stage, children and adults have only one or several rashes (and recurrences), especially in the hands, upper arms, before elbows or behind knees.

Although the color, intensity and location of the rash are different, it is always itchy. Severe itching is the main symptom in older children and adults. Itching often leads to uncontrollable scratching and a series of itching-scratching-itching, which makes the problem worse. Persistent scratches can cause the skin to thicken (covered with moss).

Scratching and rubbing can also tear the skin, leaving an opening for bacteria to enter, and leading to infection of the skin, subcutaneous tissue and nearby lymph nodes. There may also be extensive inflammation and skin exfoliation (exfoliative dermatitis).

In people with atopic dermatitis, infection with herpes simplex virus (in other people, a small area of mild painful blisters is usually infected) may lead to serious diseases, accompanied by extensive dermatitis, blisters and high fever (eczema and herpes).

Patients with atopic dermatitis may also suffer from viral skin infections (such as verruca vulgaris and molluscum contagiosum) and fungal skin infections.

People with atopic dermatitis for a long time may have opacification of eyeball lens (cataract) in their twenties and thirties.

* The appearance of rash and the person's family history.

* Sometimes it is a skin test or blood test.

Doctors diagnose atopic dermatitis according to the typical appearance of rash and whether other family members have allergic reactions.

Sometimes, doctors will conduct skin prick test, patch test or blood test ([RAST]) to determine which substances may cause seizures.

Atopic dermatitis usually decreases under 5 years old. However, epilepsy is common throughout adolescence and adulthood. Girls and people with atopic dermatitis in their early years have serious diseases, family history, rhinitis or asthma, and are likely to suffer from atopic dermatitis for a long time. However, even among these people, atopic dermatitis is often significantly relieved or alleviated in adulthood. Because the symptoms of atopic dermatitis are visible and sometimes disabling, long-term emotional problems may occur when children face the challenge of coexisting with diseases during their development.

Avoiding contact with substances that are known to irritate the skin or foods that are sensitive to people can prevent rashes.

Some measures help to reduce the impact on common family triggers:

* Use synthetic fiber pillows and impervious mattress covers.

* Wash bedding with hot water.

* Remove upholstered furniture, plush toys, carpets and pets (to reduce dust mites and animal dander)

* Use air circulators with HEPA filters in bedrooms and other places where people often live.

* Use dehumidifiers in basements and other damp rooms with poor ventilation (to reduce mold).

People should also try to relieve their emotional stress.

* Anti-itching measures

* Measures to reduce exposure to trigger substances

There is no cure, but topical or oral drugs can relieve itching (see itching: treating itching). Treatment can usually be done at home, but people with exfoliative dermatitis, cellulitis or eczema and herpes may need hospitalization.

Some skin care measures are very helpful:

* Replace ordinary soap with soap substitutes.

* Keep your skin moist, whether it is commercial moisturizing cream or water after contact with vaseline or vegetable oil.

* Apply moisturizing cream immediately after bathing and keep your skin moist.

* Take a bath only once a day.

* Take a bath in water diluted with bleach or colloidal oatmeal.

* Dry or pat the skin after bathing, and don't rub it.

Parents should cut their children's nails short to reduce scratches and thus reduce the risk of infection.

Specific treatment methods include the use of corticosteroid ointment or cream. In order to limit patients who receive corticosteroid therapy for a long time, doctors sometimes use vaseline instead of corticosteroids for a week or more. Ointments or creams containing immune system regulating drugs (such as tacrolimus or pimecrolimus) are also useful, which can limit the need for long-term use of corticosteroids. Some doctors will prescribe this medicine first. Corticosteroid tablets are the last resort for patients with stubborn cases.

Phototherapy (exposure to ultraviolet rays) may help adults (see phototherapy). If possible, children and young people can avoid this treatment because it may lead to long-term side effects, including skin cancer and cataracts.

In severe cases, cyclosporine, azathioprine or mycophenolate mofetil can be taken orally or interferon γ can be injected to suppress the immune system.

Treatment of herpetic eczema with antiviral drug acyclovir.

By who? Karen McCoy, MD, Master of Public Health, Assistant Clinical Professor of Dermatology; Senior staff of Harvard Medical School; Laxi clinic dermatology