Clinically there is no itchy dermatitis the diagnosis, the whole body itching may be due to allergic skin diseases, underlying diseases, geriatric pruritus and other factors. 1. Allergic skin diseases: urticaria, eczema, contact dermatitis, etc., can appear all over the body itching phenomenon, usually due to food, drugs, environmental factors such as substance contact. 2. Underlying diseases: if you suffer from diabetes, dry syndrome, endocrine function abnormalities and other diseases, can also appear the phenomenon of itching. 3. Geriatric pruritus: the elderly due to ageing, skin oil secretion is reduced, the skin function barrier is damaged, so it is easy to appear all-over itching phenomenon. The causes of generalized itching are very many, it is recommended that patients go to the hospital in a timely manner to improve the examination, through the examination to clarify the factors of generalized itching, and then according to the cause of the standardized treatment, not to be handled indiscriminately, so as to avoid inducing adverse consequences.