Itchy buttocks consider the following aspects of the cause: the first case, is due to anal laxity, the rectum of a large number of intestinal fluid out of the anus, stimulation of the anal skin, resulting in itching; the second case, commonly found in sexually transmitted infections, common infections is the HPV viral infections such as condyloma acuminatum, will grow a lot of skin flabs, with the lengthening of time, more and more and more, bigger and bigger, was the pattern of vegetables and accompanied by itching; the third case, seen in perianal eczema, due to special parts of the buttock groin is deeper, so it is easier to keep dry in the anal cavity of obese patients. The third condition, seen in perianal eczema, is due to the special location of the buttock groove of obese patients is deeper, so the anus is more difficult to keep dry. Especially in summer, perianal eczema is more likely to occur, and scratching stimulation can aggravate the itching. The fourth situation, seen in parasitic infections, common parasitic infections for roundworms and pinworms, at the same time can be seen in the anus with eggs; the fifth situation, seen in intimate apparel allergies, such as women appear to be allergic to sanitary napkins.