The uncomfortable feeling of swelling in the anus often suggests the following diseases: first, perianal abscess. This disease is essentially an infection of the fatty tissue under the skin of the perianal area, and the patient will feel a swollen and even painful sensation in the anus. Second, anal fistula. The actual fact is that you can find a lot of people who are not able to get a lot of money for the purpose of the actual project. The third is the prolapse of the internal hemorrhoids of mixed hemorrhoids.