What is eczema?
Eczema is a disease caused by inflammation of the skin and the skin's inability to retain adequate moisture. The result is a dry and very troublesome rash and intense itching, which may occur on almost any part of the body.
Impairment of natural skin barrier
In normal, healthy skin, which is pliable and elastic, a controlled amount of water is permitted to pass through the layers of the skin to ensure that the outermost areas remain properly hydrated.
A number of factors may result in the impairment of the natural skin barrier function: genetics, allergens, washing chemicals etc. As a result, the skin may become more susceptible to skin disease and more sensitive to the repeated use of water, detergents and other irritants. It will also lose its ability to retain moisture.
Eczema is largely a disease of childhood, but also affects adults. This is a condition that may commence a few weeks after birth, but usual onset is after the third month of life.
In babies, eczema may appear as a weepy rash on the face and inner creases or outer surfaces of arms and legs. In severe cases it may involve the whole body. Heavy scaling, similar to cradle cap, may occur.
In later childhood it becomes a dry, scaly, itchy rash mostly affecting the inner creases of the elbows and knees. Some children may not outgrow eczema and the condition then continues into adulthood. In teenagers and young adults the creases of the elbows and knees, the face (especially around the eyes), hands and feet are frequently affected.
Although incidence varies depending on the severity, an estimated 50% of children with eczema develop allergic rhinitis; while between 20% and 30% develop asthma.
In time, around 50% of children with eczema undergo complete, spontaneous resolution.
One of the prominent symptoms is intense itching (pruritus). Scratching or rubbing the affected skin causes further release of irritating chemicals in and under the skin. These chemicals further irritate the skin and increase itchiness, which in turn increases scratching.
Ensure therefore that fingernails are clean and cut short and that medication is sufficient to abolish this symptom. An increased dose or change of medication may be required.
Not all rashes in children are eczema. Several rashes may mimic eczema, for example nappy rash, seborrhoeic dermatitis, contact dermatitis and psoriasis. That is why it is important for a doctor to make the diagnosis of eczema and to rule out other causes.
Contact dermatitis is a rash that develops after contact with substances such as nickel, latex, dishwashing liquid and working with raw vegetables. These skin diseases may look similar to eczema, but are caused by different factors and are treated differently.
Reviewed by Professor Sharon Kling, Clinical Unit Head, General Paediatrics, Intensivist at Tygerberg Hospital and Associate Professor, Department of Paediatrics and Child Health at Stellenbosch University. February 2015.
Original article by Dr Harris Steinman, May 2007.