Itchy skin allergy common in children

By DR LEO REVELL - Waikato Times | View original article..

Thursday, 28 June 2007

Itchy patches of skin are the first signs of eczema, a common condition but one that needs treating, says Times medical correspondent Dr Leo Revell.

What is atopic eczema?

This is a chronic inflammation of the skin that seems to be caused by allergies. People with atopic eczema usually have other family members with the problem.

It is most common in children, but a small number of people with eczema continue to have it as they grow older. The common name for the condition is eczema. Some doctors call the condition atopic dermatitis or just dermatitis.

What are the symptoms of atopic eczema?

People with eczema get very itchy patches of skin with tiny red spots in them and the skin can be scaly. The common places for babies and small children to get eczema are on the face, cheeks, arms, legs and body. As children get older the eczema often occurs in the creases at the elbows and behind the knees and in the creases of the neck. Your family doctor can diagnose the problem for you. The doctor diagnoses the condition if a child has an itchy rash, there is eczema or asthma or hay fever in the family and the problem began when the child was young.

What does atopic mean?

Atopic means allergic. People are called atopic if they have allergic hay fever, eczema or asthma.

Who gets atopic eczema?

Eczema is common and between one in 10 and one in four people in various parts of the world suffer from the problem. It is more common in cities and in richer parts of the world.

What causes atopic eczema?

Most people with eczema have high blood levels of the antibodies that cause allergies. They often have positive skin allergy tests to pollens, house dust mites and cat, dog or horse hair. Some have allergies to certain foods. Researchers believe that eczema is a condition of the immune system. The immune system normally fights off infections, but in eczema, the immune system seems to attack the skin and damage it.

The condition seems to be inherited, because identical twins are both very likely to have eczema, while non-identical twins have about the same risk brothers and sisters would normally have. About one in two people with eczema have a family history of hay fever or asthma, which are also thought to be allergic conditions.

A patch of eczema is itchy and the child scratches the spot. This causes the skin to become more inflamed and the top layer of skin comes off. The area can weep like a graze and become infected. The infections that occur can be due to bacteria, most commonly staphylococcus, fungus or viral infections such as herpes simplex, the virus that causes cold sores. The infection can cause worse eczema and sometimes the doctor needs to give antibiotics to clean out infection before the eczema can improve.

A fungus that can aggravate eczema is malassezia furfur. This fungus is quite common on the body, shoulders, scalp and face and is a very common cause of dandruff. Certain medicated shampoos such as Selsun and Nizoral shampoos can help clear this not only from the scalp, but also from the face and body. If a child gets a herpes infection in the eczema, this can be extremely serious and usually the child needs to go to hospital for intensive antiviral antibiotic treatment.

One reason children get worse eczema is because washing can remove the natural oils from the skin. When this happens, water evaporates from the skin and the skin becomes dry. Dry skin becomes itchier and the person scratches the skin. Soaps and detergents remove more of the natural oils from the skin and so people with eczema should use these as little as possible.

How do you treat atopic eczema?

The main ways of treating eczema are to moisturise the skin and protect it from drying by using moisturising creams, especially after a bath. Some doctors recommend showering and others recommend bathing but putting moisturising creams and ointments on the skin straight afterwards. Lotions contain a lot of water and not much oil, so they can dry the skin. Anti-inflammatory creams and ointments help settle the inflammation of the skin. Steroid creams are one type of anti-inflammatory cream and the other type is topical calcineurin inhibitors.

Steroid creams include hydrocortisone, betamethasone and mometasone creams and ointments. Topical calcineurin inhibitors include tacrolimus and pimecrolimus creams. Tacrolimus is commonly used in tablet form to stop transplant rejection. You use steroid creams once or twice a day until the eczema improves. If you properly moisturise the skin and use moisturiser to protect the skin, this often prevents the eczema returning so badly.

Skin tests can show what substances in the environment can make the eczema worse. If the person has an allergy to dust mites, you can use special covers over the mattress and pillows, and vacuum places where dust mites live. If the child is allergic to a cat or dog, they should avoid those animals. Tests can tell if someone has a food allergy. This not very common and it involves a blood test. Doctors only test for this when the eczema is not improving well with normal measures, or if certain foods seem to make the eczema worse. Foods that commonly cause an allergy in children are milk, egg, wheat, soy, corn and peanuts. A special test measures the level of allergic antibodies to these foods in the blood. If the test is positive for a particular food or foods, parents can cut the food out of the diet. If there is an infection in the skin, a long course of antibiotics can improve the eczema.

What are the side-effects of steroid creams?

There are various strengths of steroid creams. The mildest is hydrocortisone cream. If you use strong steroid creams on the face, or other sensitive parts of the body, the skin can become thinned, and when you stop using the creams, the eczema can come back worse than before. If you use hydrocortisone creams for short periods, this rebound effect is much less likely to happen.

Doctors have concerns at using large amounts of steroid creams especially on small children, because some of the steroid is absorbed through the skin. Researchers have shown that if mild steroid cream is used, this is quite rare. The steroid cream absorption could suppress the child's adrenal glands and make them less able to cope with stress.

Topical calcineurin inhibitors such as tacrolimus or pimecrolimus creams have no rebound effect when they are used. A small number of people using topical calcineurin inhibitors have developed skin cancers. The authorities say that they are safe to use in small quantities for short periods in children over the age of two where other treatments do not work or cause side-effects.

Skin specialists may use oral or injectable treatments with immune suppressing drugs for extremely severe cases. They may also use intensive light therapy to treat severe eczema.