Eczema (usually known as atopic eczema or atopic dermatitis) is an inflammatory skin disease which tends to involve areas such as the folds of the elbows or knees (skin creases). It can be chronic, intensely itchy and relapsing.

It is a worldwide problem affecting 15 to 20% of children. Around 2% of adults have the condition and many of these have a more chronic and severe form. It can also be associated with complications such as bacterial and viral infections.

Eczema is a complex disease, with many different genetic and environmental causes. External factors including house dust mites, microbes, climate, stress and air pollution have all been associated with an altered risk of developing eczema.

Chronic sleep disturbance due to itching and scratching can have a negative effect on the quality of life of the person affected. In children, the social and emotional impact on the family can be greater than that of type I diabetes.

There is a substantial economic cost not only to the family of the person with eczema but also to the country's health service. The healthcare costs of eczema in adults are comparable to those of other chronic diseases such as epilepsy.