The reason why this symptom occurs is mainly due to perianal diseases, including internal hemorrhoids, rectal prolapse and anal sinusitis. First of all, internal hemorrhoids can cause this symptom. Internal hemorrhoids mainly occur above the dentate line of the anal canal, and after they are formed, they can affect the rectal passage to a certain extent, especially the nucleus of hemorrhoids will also stimulate the surrounding mucosa and cause anal swelling symptoms, which will be relieved after exhaustion. Secondly, rectal prolapse, the mucous membrane at the end of the rectum is stimulated by bacteria for a long time will appear to proliferate inwards and also detach from the intestinal wall, the prolapsed mucous membrane will block the anus, thus causing anal swelling symptoms. Sinusitis can also cause this symptom, because of the special location of the anal sinus, easy to be stimulated by feces and bacteria for a long time, thus causing inflammation of the anal sinus and blocking the anus.