Eczema | Causes and Treatment | Patient

What is atopic eczema?

Eczema is sometimes called dermatitis which means inflammation of the skin. There are different types of eczema. The most common type is atopic eczema. In this type of eczema there is a typical pattern of skin inflammation which causes the symptoms.

The word atopic describes people with certain allergic tendencies. However, atopic eczema is not just a simple allergic condition. People with atopic eczema have an increased chance of developing other atopic conditions, such as asthma and hay fever.

Typically, inflamed areas of skin tend to flare up from time to time and then tend to settle down. The severity and duration of flare-ups varies from person to person and from time to time in the same person.

Most cases first develop in children under the age of five years. Current figures suggest about 1 in 5 schoolchildren have some degree of atopic eczema. However, statistics show that it is becoming more common year on year.

By the mid-teenage years the flare-ups of eczema have either gone completely, or are much less of a problem for 2 out of 3 young people. However, there is no way of predicting who will still be affected as adults.

It is unusual to develop atopic eczema for the first time after the age of 20. About one in thirty adults have eczema.

The cause is not fully understood. The oily (lipid) barrier of the skin tends to be reduced in people with atopic eczema. This leads to an increase in water loss and a tendency towards dry skin. Also, some cells of the immune system release chemicals under the skin surface, which can cause some inflammation. But it is not known why these things occur. Inherited (genetic) factors play a part. Atopic eczema occurs in about 8 in 10 children where both parents have the condition and in about 6 in 10 children where one parent has the condition. The precise genetic cause is not clear (which genes are responsible, what effects they have on the skin, etc). However, recent research suggests that in some people genetic changes hamper the production of a chemical (filaggrin) involved in the defence barrier of the skin.

As mentioned previously, atopic eczema is becoming more common. There is no proven single cause for this but factors which may play a part include:

There may be a combination of factors in someone who is genetically prone to eczema, which causes the drying effect of the skin and the immune system to react and cause inflammation in the skin.

The usual treatment consists of three parts:

Many people with atopic eczema have flare-ups from time to time for no apparent reason. However, some flare-ups may be caused (triggered) or made worse by irritants to the skin, or by other factors. It is commonly advised to:

House dust mite is a tiny insect that occurs in every home. You cannot see it without a microscope. It mainly lives in bedrooms and mattresses as part of the dust. Many people with atopic eczema are allergic to house dust mite. If you are allergic, you have to greatly reduce the numbers of house dust mite for any chance that symptoms may improve.

However, it is impossible to clear house dust mite completely from a home and it is hard work to reduce their number to a level which may be of benefit. It involves regular cleaning and vacuuming with particular attention to your bedroom, mattress and bedclothes.

Therefore, in general, it is not usually advised to do anything about house dust mite - especially if your eczema is mild-to-moderate and can be managed by the usual treatments of emollients and short courses of topical steroids. However, if you have moderate or severe atopic eczema which is difficult to control with the usual treatments, you may wish to consider reducing the number of house dust mites in your home. See the separate leaflet called House Dust Mite and Pet Allergy, which gives more details on how to reduce house dust mites.

About 1 in 2 children with atopic eczema have a food allergy which can make symptoms worse. In general, it is young children with severe eczema who may have a food sensitivity as a trigger factor. The most common foods which trigger symptoms in some people include cow's milk, eggs, soya, wheat, fish and nuts.

If you suspect a food is making your child's symptoms worse then see a doctor. You may be asked to keep a diary over 4-6 weeks. The diary aims to record any symptoms and all foods and drink taken. It may help to identify one or more suspect foods. If food allergy is suspected, it should be confirmed by a specialist. They may recommend a diet without this food if the eczema is severe and difficult to control by other means.

Other possible factors which may trigger symptoms, or make symptoms worse, include:

However, some of these may not be avoidable.

See the separate leaflet in this series, called Eczema Triggers and Irritants, for more details.

People with atopic eczema have a tendency for their skin to become dry. Dry skin tends to flare up and become inflamed into patches of eczema. Emollients are lotions, creams, ointments and bath/shower additives which prevent the skin from becoming dry. They oil the skin, keep it supple and moist and help to protect the skin from irritants. This helps to prevent itch and helps to prevent or to reduce the number of eczema flare-ups.

The regular use of emollients is the most important part of the day-to-day treatment for atopic eczema. Your doctor, nurse or pharmacist can advise on the various types and brands available and the ones which may suit you best.

You should apply emollients as often as needed. This may be twice a day, or several times a day if your skin becomes very dry. Some points about emollients include:

Many people with atopic eczema use a range of different emollients. For example, a typical routine for a person with moderately severe atopic eczema might be:

Note: emollients used for eczema tend to be bland and non-perfumed. Occasionally, some people become allergic (sensitised) to an ingredient in an emollient. This can make the skin worse rather than better. If you suspect this, see your doctor for advice. There are many different types of emollients with various ingredients. A switch to a different type will usually sort out this uncommon problem.

Warning: bath additive emollients will coat the bath and make it greasy and slippery. It is best to use a mat and/or grab rails to reduce the risk of slipping. Warn anybody else who may use the bath that it will be slippery.

See the separate leaflet called Moisturisers for Eczema (Emollients) for more details.

Topical steroids work by reducing inflammation in the skin. (Steroid medicines that reduce inflammation are sometimes called corticosteroids. They are very different to the anabolic steroids which are used by some bodybuilders and athletes.) Topical steroids are grouped into four categories depending on their strength - mild, moderately potent, potent and very potent. There are various brands and types in each category. For example, hydrocortisone cream 1% is a commonly used steroid cream and is classed as a mild topical steroid. The greater the strength (potency), the more effect it has on reducing inflammation but the greater the risk of side-effects with continued use.

Creams are usually best to treat moist or weeping areas of skin. Ointments are usually best to treat areas of skin which are dry or thickened. Lotions may be useful to treat hairy areas such as the scalp.

As a rule, a course of topical steroid is used when one or more patches of eczema flare up. You should use topical steroids until the flare-up has completely gone and then stop them. In many cases, a course of treatment for 7-14 days is enough to clear a flare-up of eczema. In some cases, a longer course is needed. Many people with atopic eczema require a course of topical steroids every now and then to clear a flare-up. The frequency of flare-ups and the number of times a course of topical steroids is needed can vary greatly from person to person.

It is common practice to use the lowest-strength topical steroid which clears the flare-up. If there is no improvement after 3-7 days, a stronger topical steroid is usually then prescribed. For severe flare-ups a stronger topical steroid may be prescribed from the outset. Sometimes two or more preparations of different strengths are used at the same time. For example, a mild steroid for the face and a stronger steroid for patches of eczema on the thicker skin of the arms or legs.

For adults, a short course (usually three days) of a strong topical steroid may be an option to treat a mild-to-moderate flare-up of eczema. A strong topical steroid often works quicker than a mild one. (This is in contrast to the traditional method of using the lowest strength wherever possible. However, studies have shown that using a high strength for a short period can be more convenient and is thought to be safe.)

Some people have frequent flare-ups of eczema. For example, a flare-up may subside well with topical steroid therapy. But then, within a few weeks, a flare-up returns. In this situation, one option that might help is to apply steroid cream on the usual sites of flare-ups for two days every week. This is often called weekend therapy. This aims to prevent a flare-up from occurring. In the long run, it can mean that the total amount of topical steroid used is less than if each flare-up were treated as and when it occurred. You may wish to discuss this option with your doctor.

Topical steroids are usually applied once a day but this may be increased to twice a day if there is no improvement. Rub a small amount thinly and evenly just on to areas of skin which are inflamed. (This is different to moisturisers which should be applied liberally all over.)

To work out how much you should use each dose: squeeze out some cream or ointment from the tube on to the end of an adult finger - from the tip of the finger to the first crease. This is called a fingertip unit. One fingertip unit is enough to treat an area of skin twice the size of the flat of an adult's hand with the fingers together. Gently rub the cream or ointment into the skin until it has disappeared. Then wash your hands (unless your hands are the treated area).

Note: don't forget you can use emollients as well when you are using a course of topical steroids.

See the separate leaflet called Fingertip Units for Topical Steroids for more details.

Short courses of topical steroids (fewer than four weeks) are usually safe and normally cause no problems. Problems may develop if topical steroids are used for long periods, or if short courses of strong topical steroids are repeated often. The concern is mainly if strong topical steroids are used in the long term. Side-effects from mild topical steroids are uncommon.

For more details about side-effects see the separate leaflet called Topical Steroids for Eczema.

Most people with eczema will be prescribed emollients to use every day and a topical steroid to use when flare-ups develop. When using the two treatments, apply the emollient first. Wait 10-15 minutes after applying an emollient before applying a topical steroid. That is, the emollient should be allowed to sink in (be absorbed) before a topical steroid is applied. The skin should be moist or slightly tacky but not slippery, when applying the steroid.

Sometimes, one or more patches of eczema become infected during a flare-up. Characteristics of infected eczema include:

If the infection becomes more severe, you may also develop a high temperature (fever) and generally feel unwell. If infected eczema develops then a course of an antibiotic tablet or liquid medicine will usually clear the infection. This is used in addition to usual eczema topical treatments. Sometimes, a topical antibiotic is used if the infection is confined to a small area. There is a rare condition where eczema becomes infected with a virus called herpes simplex. This requires antiviral medication rather than antibiotics. See the separate leaflet called Eczema Herpeticum for more details.

Once the infection is cleared, it is best to throw away all your usual creams, ointments and lotions and obtain fresh new supplies. This is to reduce the risk of applying creams, etc, that may have become contaminated with germs (bacteria). Also, if you seem to have repeated bouts of infected eczema, you may be advised to use a topical antiseptic such as chlorhexidine on a regular basis. This is in addition to your usual treatments. The aim is to keep the number of bacteria on your skin to a minimum.

See your doctor if a flare-up of atopic eczema is getting worse or not clearing despite the usual treatments with moisturisers (emollients) and topical steroids. Things which may be considered include:

You may be referred to a skin specialist if a flare-up does not improve with the usual treatments.

Alternative remedies such as herbal medicines are sometimes tried by some people. However, you should be cautious about using them, especially if their labels are not in your usual language and you are not sure what they contain. Some herbal treatments are mixed with steroids and some (particularly Chinese remedies) have been linked to liver damage.

It may be worth breastfeeding a newborn baby for three months or more if several members of the family suffer from allergies such as eczema, hay fever or asthma. There is, however, no evidence to suggest that the mother should avoid any particular foods during pregnancy or breastfeeding.

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Eczema | Causes and Treatment | Patient