Eczema can occur in all parts of the body and it has different manifestations for adults and children, men and women. Eczema has a wide range, and less eczema confined to the back. The causes of eczema on the back are as follows: 1. internal causes: damp heat in Chinese medicine and metabolic abnormalities in Western medicine; 2. external causes: eczema triggered by contact with moist, hot and humid objects. In addition, the causes vary by age, gender, and season. The real cause of eczema is not clear, mostly related to allergies, but most of the skin allergies for which the cause can be determined are dermatitis, and those for which the cause is not determined are called eczema.