Atopic eczema is an inflammatory condition of the skin. Atopic is the term used to describe conditions such as eczema, asthma, seasonal rhinitis and hay fever, which often have a genetic basis. Eczema is the term used to describe changes in the upper layer of the skin that include redness, blistering, oozing, crusting, scaling, thickening and sometimes pigmentation (although not all of these changes will necessarily occur together). The words eczema and dermatitis are interchangeable and mean the same thing: thus atopic eczema is the same as atopic dermatitis.

Atopic eczema affects both sexes equally and usually starts in the first weeks or months of life. It is most common in children, affecting at least 10% of infants at some stage. It usually disappears during childhood, although it can carry on into adult life or come back in the teenage or early adult years. It may occasionally develop for the first time in adulthood.

A tendency to atopic conditions often runs in families (see below) and is part of your genetic make-up. In people with atopic eczema, the function of their skin as a barrier to the outside world does not work well, so that irritant and allergy-inducing substance enter their skin, and may cause dryness and inflammation. Atopic eczema is not catching.