Eczema, an inflammation of the superficial dermis and epidermis caused by a variety of internal and external factors. The etiology is unknown and may be related to the following factors: 1. Internal factors: chronic infectious lesions, such as chronic cholecystitis, tonsillitis, parasitic diseases, etc.; endocrine and metabolic changes, such as menstrual disorders, pregnancy, etc.; blood circulation disorders, such as varicose veins in the lower legs, etc.; neuropsychiatric factors; genetic factors, the latter related to individual susceptibility. 2. External factors: eczema can occur from food, such as fish, shrimp beef and mutton, etc.; inhalants, such as pollen, house dust mites, etc.; living environment, such as heat; animal fur; various chemical substances, such as cosmetics, soap, synthetic fibers, etc. triggered and aggravated. The occurrence of eczema is associated with the interaction of various internal and external factors, and a few may be mediated by delayed hypersensitivity reactions.