The term ‘eczema’ is used interchangeably with ‘dermatitis’ and refers to inflammation of the skin. It is a highly individual condition that varies from person to person and comes in many different forms. In mild cases, the skin is dry, red and itchy; while in more severe cases, the skin may ooze, crust or bleed. The skin may also become infected following breaks in the skin caused by scratching.
Eczema affects 1 out of 10 people (10%) at some time in their life. Although most often seen in children, it can affect all age groups.
Atopic eczema is the most common type of eczema. However, there are many other types of eczema as well. Atopy is characterised by a tendency to develop a group of hypersensitivity disorders; namely eczema, asthma or hay fever, due to a genetic predisposition.
This is most commonly seen in babies (where it often clears by 2 months of age) although it also occurs in adults. It is seen on the oily areas of the body such as the scalp, face, upper chest, back and groin. The cause of seborrhoeic dermatitis is not clear. In infants, the condition is believed to be related to developing sebaceous (oil) glands; while in adults, it is thought to involve an inflammatory reaction to an overgrowth of malassezia yeasts. Seborrhoeic dermatitis is either not itchy or just mildly itchy. There is a greasy, yellow scaly rash on the affected areas. When the scalp is affected, dandruff is seen.
Seborrhoeic dermatitis on the face with greasy yellow scales.
This presents with itchy, scaly, coin-shaped patches which tend to blister and weep. It commonly occurs on the arms and legs of young adults. The cause is unclear, but it is associated with dry skin, the use of irritants (eg soap, detergents) and previous atopic eczema.
Discoid eczema on the limbs.
This form of eczema is due to extreme dryness of the skin, especially the arms and legs of elderly people. It presents with an itchy, scaly, red rash that looks like ‘cracked tiles on the floor’. It is associated with a decrease in the natural oils produced by the skin, and over-cleansing of the skin (especially with hot water).
Asteatotic eczema with appearance of “cracked tiles on the floor”.
This is also known as varicose, gravitational or stasis eczema. It is commonly seen in the elderly and people with varicose veins in the legs. The pooling of blood in the leg veins due to gravity leads to this form of eczema. The legs may become swollen, especially at the end of the day or after prolonged standing. There may also be associated discolouration of the skin, as well as skin tightening and thickening.
Venous eczema on the left leg due to varicose veins.
There are two types – irritant and allergic. Irritant contact dermatitis is caused by exposure to irritant substances such as soaps, detergents, bleach and engine oils. However, even excessive exposure to water alone can cause irritant contact dermatitis. Allergic contact dermatitis is caused by a specific hyper-sensitivity to substances such as nickel, epoxy glue, hair dye and fragrance/perfume. A patch test is done to identify any allergen. Avoidance of the irritant or allergen should lead to improvement of this type of eczema.
Nickel allergy-contact dermatitis on the abdomen around the umbilicus due to belt buckle
The following are important in the skin care of people with atopic eczema:
Treatments commonly prescribed for eczema include moisturisers and topical steroids. Topical steroids are useful in reducing skin inflammation. They are safe if used appropriately. Some possible side effects of prolonged use of steroids include skin thinning. Your doctor will advise on the appropriate use of topical steroids.
More recently, steroid-free topical medications have been developed and are available for the treatment of eczema. These new TCI creams (tacrolimus, pimecrolimus) are costly and your doctor will assess the suitability and appropriate use of these medications.
Oral treatments for eczema include oral antibiotics when the skin is infected. Antihistamines are also commonly prescribed to reduce the itch. In severe cases of atopic eczema, other treatment options such as phototherapy or systemic immunomodulators may be indicated. Your doctor will advise you accordingly.
It is rare for food allergies to cause eczema, although food allergies may make eczema worse in some people. Prevalence of food allergies is highest in young children with severe eczema. It may be present in about one third of children less than 3 years of age with severe eczema. In adults, food allergy is very uncommon. Common food allergens in children include cow’s milk, hen’s egg, peanut, tree nuts, shellfish, wheat and soy.
Screening tests for food allergy include skin prick test and specific IgE blood test. The results of these tests must be interpreted by an experienced dermatologist.