Eczema is a common skin disease with the pathogenesis of delayed hypersensitivity. It is usually caused by the interaction between some external stimuli and sensitive factors within the body, thus its cause-effect relationship is relatively complicated. For example, animal and plant factors and various intensifying stimuli can all induce this disease. Therefore, it is often difficult to cure even after the removal of external causes. The main clinical features are multiple types of rash lesions, tendency to exudation, severe itching, extensive or symmetrical distribution, longer course of disease, and prone to chronicity. Eczema can occur in any age group without gender difference.