Eczema is a pattern of itchy skin rash consisting of tiny pink bumps that may join together, producing ill-defined pink or red patches. There are many types of eczema – some have known causes. Dermatitis is the term used for eczema reactions that are caused by external agents/factors. Atopic eczema is often referred to as “infantile” or childhood eczema because that is when it usually develops. Atopic eczema is usually associated with allergies (hay fever or asthma) in either the affected individuals or in their close relatives.
Eczema changes with age. It commonly begins in infancy as dry patches which may be inflamed (pink) and may also be wet/oozy. The affected areas can be very extensive, affecting the face and head in particular, as well as the body and limbs, but it often spares deep folds (armpits and groin). As the baby starts crawling, eczema usually becomes localised to sites in close (frictional) contact with the environment – fronts of knees, wrists, and ankles. When the child starts walking, eczema tends to be localised to the fronts of the elbows, backs of the knees, neck, and face. Eczema may range in severity from mild and easily controlled to extensive, severe, and very difficult to control.
Other types of eczema/dermatitis that can be confused:
Causation/aggravation of atopic eczema
There is a strong genetic/inherited susceptibility to developing atopic conditions including eczema. The genetic abnormalities affect the effectiveness of the permeability barrier of the skin surface and the control of the immune system, resulting in allergies. Eczema is easily irritated and aggravated by soaps and scents, cold and extremes of dryness or humidity. Increased colonisation of the skin by bacteria can flare eczema. Emotional stress is an important trigger in many individuals.
Role of allergy
Atopic eczema can be triggered by an allergy to a range of foods or airborne allergens. 30–40% of children with moderate to severe eczema may have food allergies that worsen their skin symptoms.
In older children and adults, food allergy is much less common, while house dust mites, pollens, and animal furs may be significant provoking factors. Testing for allergic triggers is very unreliable, as positive skin tests can be found in 70–80% of patients, but this does not indicate how much the allergy contributes among the many other factors.
Treatments
Moisturisers (also called emollients) are fundamental to the management of a topic eczema. They serve as primary treatment that targets the underlying skin barrier dysfunction and helps to maintain hydration, repair the barrier and reduce inflammation. Corticosteroid creams/ointments are used to suppress eczema flare and inflammation. There are four categories, from weak (Hydrocortisone) through potent (Betnovate) to super potent (Dermovate). Recently, non-steroid creams (Protopic and Elidel) have become available. Regular use of moisturisers can soothe the itch. Infection requires antibiotics. In people with definite allergic provocation, avoidance of allergens can be helpful.