An anal fistula is an abnormal tube-like connection that forms between the inside of the anus at the anal gland and the skin right outside the anus. Think of it as a tunnel. The abscess that causes the fistula is quite painful. It can cause intense pain and swelling around the anus. This pain gets worse with bowel movements. You may also have a fever and bleeding around the area.
The anus is an opening at the lower back of the body which helps expulsion of faces from the body. Small glands are present inside the anus. A fistula is a severe case when one of these glands gets blocked thereby leading to the formation of an abscess or an infected cavity. Few of these abscess has the capability to self-drain whereas few need surgical treatment for the same. When a tunnel is created between the anus and the infected glands within the anus to a skin opening adjacent to the anus, fistula builds up. For the majority of the cases, an anal fistula is the direct outcome of the abscess formed inside the anus. In the inner lining of the anus, some glands form fluids.
An anal abscess is an infected cavity filled with pus found near the anus or rectum. Ninety percent of abscesses are the result of an acute infection in the internal glands of the anus. Occasionally, bacteria, fecal material or foreign matter can clog an anal gland and tunnel into the tissue around the anus or rectum, where it may then collect in a cavity called an abscess.
The anus is the external opening through which feces are expelled from the body. Just inside the anus are a number of small glands. If one of these glands become blocked, an abscess — an infected cavity — may form. An anal abscess is usually treated by surgical drainage, although some drain spontaneously.