The itchy buttocks after hemorrhoid surgery may be caused by the following conditions: 1. local infection may occur, mostly due to the infection of the wound with water or clothing bacteria after surgery, resulting in local itching, pain and inflammation. 2. it may be due to an allergic reaction of the patient’s skin around the anus to the drug, with the typical symptom of local itching and pain. 3. 3. It is also possible that the patient has local eczema, which may result in small blister-like herpes with a flushed base and unbearable itching. In addition, it cannot be ruled out that it is caused by a perianal abscess or poor surgical healing, so it is best to inform your doctor and treat it accordingly.