Eczema is a common chronic skin condition that affects about 15% of the population. In most individuals it starts before age five. The most common complaint is dry scaly skin that can occur all over the body. The skin can be thickened with creasing often evident on the face or with fissures (or cracks) in the skin especially on the hands and feet. It is also associated with blocking hair follicles (causing bumps on the skin) and increasing pigmentation of the skin, especially in people of darker complexion.
Although the full cause of eczema has not been determined, experts agree that it has a strong genetic component. People with eczema have an increased frequency of other diseases such as asthma, nasal allergy and food allergy (which also tend to run in families). Specific genetic defects are starting to be identified including mutations in genes that code for specific proteins such as filaggrin, which are important in maintaining a normal protective skin barrier.
There are no specific blood tests available to diagnose eczema. Skin biopsies are seldom helpful except when a very unusual appearance makes it necessary to rule out other skin conditions. The diagnosis depends on the symptoms and appearance over time.