1, the skin itself disease itch: common causes such as atopic dermatitis, eczema, maculopathy, urticaria, itchy rash, etc., have very intense itching; 2, external factors caused by itching: external factors are very much, such as contact with glass fiber, peach hair, etc. caused by irritant dermatitis; contact with paint, glue, cosmetics, metal, etc. caused by allergic contact dermatitis; parasites such as scabies caused by scabies, lice disease, etc. Will trigger intense itching; at this time, the skin will also have corresponding changes; 3, itching caused by visceral lesions: liver, kidney, endocrine, tumors, etc. can cause chronic persistent itching, the skin does not necessarily have a rash; 4, drug itching: mainly caused by the use of drugs. It should not be ignored; 5, neurological, psychiatric pruritus: the nervous system, including brain lesions can cause pruritus; simple mental illnesses such as delusional disorder, can also cause. The treatment of itching should not simply stop itching, but should carefully find the causes from the above five aspects.