There are many reasons why the body is always itchy, the common ones are as follows: i. Allergic skin diseases, such as atopic dermatitis, acute and chronic urticaria, drug rash, etc. Second, non-allergic skin diseases, such as psoriasis, neurodermatitis, seborrheic dermatitis, etc. Third, elderly itchy skin, dry skin in the elderly, can cause itching. Fourth, pregnant women, pregnant women have increased bile acids, which can cause itchy skin. V. Physical factors, cold, heat, friction, mental tension, etc. Six, disease caused by, for example, diabetes, hyperthyroidism, liver and kidney insufficiency, etc. Seven, other factors, such as scabies infection, lice disease, etc.