Many perianal diseases can cause anal soreness and swelling, including hemorrhoids, rectal prolapse, and sinusitis: first of all, hemorrhoids are the most common cause of hemorrhoids, which are mostly caused by varicose veins around the anus and can form thrombi or venous clusters around the anus. These thrombi or venous clusters are mostly located under the skin, and when they form, they cause pain and swelling in the anal area, so they can lead to soreness and swelling. Secondly, rectal prolapse can also lead to anal soreness and swelling. Repeated bacterial infections cause the mucous membrane in the rectum to detach from the intestinal wall, which is also the main cause of rectal prolapse, and the prolapsed rectal tissue will pull the anus, causing anal soreness and swelling. In addition, due to the special location of the anal sinus, it is often susceptible to bacterial infection causing hyperplasia or inflammation, resulting in inflammatory symptoms of the anal sinus and increasing the burden on the anus, causing symptoms of anal soreness and swelling.