When perianal abscesses occur, there are usually significant triggers, most commonly seen after acute diarrhea or when a patient's immunity has recently declined. In the early stages of a perianal abscess, there are sudden symptoms of localized swelling and pain around the anus, accompanied by a sensation of heaviness. As the local abscess cavity enlarges and the infection worsens, the patient may also experience general weakness, fever, and even a decrease in appetite. During the acute phase of a perianal abscess, due to severe local pain, patients are unable to carry on with normal life activities, including sitting and walking. The pain may further involve pelvic muscles and nerves, leading to difficulties with defecation and urinary retention.