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What is eczema?
Eczema, also known as atopic dermatitis, is an allergic condition that causes your skin to become red, dry, itchy and scaly. In severe cases, your skin may also weep, bleed or crust over. The medical term 'atopic' means that eczema often occurs in people with other allergic conditions, such as asthma or hay fever. Although eczema can occur at any age, it usually appears in early childhood. Most children grow out of it by the age of six, but for some people it can continue on into adulthood.
While the exact cause of eczema is unknown, it tends to run in families, indicating that genes related to the condition may be passed down from parents to their children. An allergic reaction to certain substances or foods can bring on eczema or it may be triggered by other factors such as stress, exercise or harsh household products.
Although there is no cure for eczema, it can usually be controlled with self-care measures or over-the-counter medications. Stronger medications are usually only required if your eczema is severe or it causes a skin infection.
Eczema occurs when the skin barrier does not work as well as it should. Moisture is easily lost from the skin, causing it to dry out. When this occurs, irritating substances can enter through gaps in dry and scaly skin. Activation of the immune system by these irritants produces inflammation, which makes the skin red and itchy. Eczema is not contagious and so cannot be passed from one person to another.
Some factors that can contribute to eczema include:
Eczema is thought to be a largely inherited condition, meaning that you're more likely to develop the condition if one or both parents have experienced eczema.
A particular gene, known as the FLG gene, has been shown to be important for the normal function and repair of the skin. Healthy skin cells have two copies of the FLG gene - one from your mother and one from your father. However, you're more likely to develop eczema if you only have one copy of the gene as your ability to repair irritated skin is reduced.
In some people, eczema results from an allergic reaction to irritating substances or foods, known as allergens. Common examples include:
- Dust mites;
- Pet hair and fur;
- Cow's milk;
- Soy, and;
Other factors that do not directly cause eczema, but may make it worse include:
- Hormonal changes, particularly due to pregnancy or menstruation;
- Cold or damp weather;
- Exposure to tobacco smoke;
- Rough or synthetic clothing;
- Washing frequently, and;
- Harsh soaps, detergents or perfumes.
Risk factors for eczema include:
There are a number of different types of eczema, including:
- Discoid eczema (nummular eczema) - coin-shaped areas of red, itchy eczema that appear mainly on the legs, buttocks and trunk for months at a time;
- Neurodermatitis (lichen simplex chronicus) - thick patches of eczema caused by scratching or rubbing healthy skin;
- Pityriasis alba - white patches usually found on the mouth and cheeks of children and adolescents, or sometimes on the neck, upper limbs and trunk;
- Dyshidrotic dermatitis - itchy eczema that tends to occur on the fingers and palms of people aged between 20 and 40 years;
- Asteatotic dermatitis - a common and very itchy form of eczema that occurs in the elderly, particularly during the winter months, and;
- Cracked hands, fingers or heels - a common cause of disability that can arise from eczema or very dry skin on the hands and feet.
Signs and symptoms
In infants, eczema usually appears on the cheeks, neck, limbs and groin. During childhood, the face often clears, but the rash may become thicker and drier. It may also appear on the hands and feet. As children grow, their skin usually becomes less dry, overheated or prone to irritation. As a result, many children grow out of eczema.
When eczema does occur in adults, it tends to appear in the creases of the elbows, behind the knees and on the hands.
Common symptoms of eczema include:
- Dry skin;
- Cracks behind the ears or in other skin creases;
- Scaly areas that are red, inflamed and itchy;
- Thickened patches of skin from scratching;
- Small, raised bumps on the skin, and;
- Crusted, weeping or cracked skin.
Inflamed areas of skin tend to flare up and then settle down in cycles. Symptoms may become more noticeable or severe during these flare-ups.
Methods for diagnosis
Your doctor will most likely diagnose eczema by looking at your skin and asking questions about your symptoms, medical history and any family members with a skin condition or allergy.
To help you figure out if any particular triggers are making your eczema worse, your doctor may conduct an allergy test or ask you to keep a food diary.
If a bacterial or viral infection is suspected, a skin swab may be sent to a laboratory for closer inspection under a microscope. In rare cases, a skin sample may be taken.
Types of treatment
There is no cure for eczema, so treatments aim to relieve symptoms by reducing inflammation and itchiness. A doctor may suggest one or more of the following treatment options:
Taking a cool bath or applying cold, wet dressings to your eczema may provide relief from pain and itching. You may also find it helpful when bathing to use mild soaps, rinse well and then dry your skin carefully. Using an emollient and putting on loose, cotton clothing is also recommended.
In infants and children, scratching may be avoided by trimming the fingernails regularly or putting cotton gloves on at night.
If the skin is inflamed, a topical corticosteroid cream may be prescribed for application directly onto your skin. Corticosteroids are usually applied together with an emollient to quickly reduce inflammation. For more severe cases, you may be prescribed a stronger option, such as hydrocortisone, clobetasone or prednisolone. It is important to take these as prescribed as certain creams cannot be used on the face and delicate areas, and long-term use can also damage the skin.
Antihistamines help to relieve itching by suppressing part of your body's natural allergic response. Some of these medications are known as 'sedating antihistamines' because they also cause drowsiness. The most common type of sedating antihistamine is diphenhydramine.
If your eczema becomes infected with bacteria, you may be prescribed an oral antibiotic in tablet or capsule form. The most common antibiotic for this type of infection is flucloxacillin, a member of the penicillin family of medications. In cases of penicillin allergy, erythromycin or clarithromycin may be used instead. Sometimes, you may need to apply a topical antibiotic cream or ointment directly onto your skin.
In children with eczema of the face and in a small number of adults, medications such as pimecrolimus may be prescribed to reduce flare-ups and maintain normal skin texture. As the name suggests, immunosuppressants work by turning down the body's overall immune response. This type of treatment is usually only used when others have not worked or have caused side effects.
The most basic forms of light therapy involve exposing your skin to a controlled level of natural sunlight. More advanced options, such as deep-penetrating light therapy, use ultraviolet (UV) light (UVA, UVB or narrow band UVB) to help control eczema. Care needs to be taken during these treatments to avoid overexposure to ultraviolet light, which is a known cause of skin cancers.
Possible complications of eczema include:
When your skin becomes dry and cracked from eczema, the risk of infection passing into your body through broken skin is increased. The most common type of bacteria that causes infection during eczema is Staphylococcus aureus. Symptoms of an infection may include:
- Oozing from cracked skin;
- Crusting, and;
- A high temperature.
It is also possible for eczema to become infected with the virus that causes cold sores, known as the herpes simplex virus (HSV). This type of infection can progress into a serious condition called eczema herpeticum. Symptoms include:
- Painful areas of eczema that quickly become worse;
- Pus-filled blisters that leave sores when they burst, and;
- A high temperature.
Severe eczema around the eyes may lead to severe eyelid itching, watering eyes, or inflammation of the eyelid (blepharitis) or eyelid lining (conjunctivitis). If left untreated, these complications can lead to permanent eye damage.
Children with eczema are more likely to experience behavioural problems than children without the condition. This may be due to psychological effects arising from bullying, sleep disturbances or self-confidence issues.
The outlook for eczema is generally good. In children, the condition often improves on its own by the age of six, but it can continue into adulthood. In adults, eczema is often a long-term or returning condition. In general, eczema may also be harder to control if it:
- Begins at an early age;
- Occurs together with allergic conditions, such as asthma and hay fever;
- Covers a large area of the body, and;
- Runs in the family.
However, eczema can usually be well controlled with relatively simple self-care measures and medications.
Methods for preventing eczema closely mirror the self-care treatment options. For example, going a day or two without bathing may help to prevent the skin from drying out. If this is not an option, you may wish to limit bathing time to around 15 minutes. Using a gentle, fragrance-free moisturiser and avoiding harsh soaps and detergents is also recommended.
Avoiding any known causes or triggers of eczema may also help to prevent eczema from flaring up or coming back.