Anal fistula is a chronic abnormal communication between the epithelialised surface of the anal canal and usually the perianal skin. They can form when anal abscesses do not heal properly. Anal fistulae originate from the anal glands , which are located between the internal and external anal sphincter and drain into the anal canal. The tract formed by this process is a fistula.
Abscess and Fistula Expanded Information
Anal fistula - Symptoms and causes - Mayo Clinic
When the area from which feces are thrown out from the body gets blocked it give rise to the formation of abscess infected cavity and such an abscess will form anal fistula. Anal fistulas are small abscess of infection inside the anus which may give rise to pain and swelling around the anus. Very often, the fistulas are formed from anal abscess but sometimes it can also occur due to sexually transmitted disease and infectious disorder like tuberculosis. The symptoms of anal fistula are bleeding, anal abscess pain with swelling, foul smelling pus discharge and occasional fever with chills.
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. An anal fistula also commonly called fistula-in-ano is frequently the result of a previous or current anal abscess.
Anal fistulas are generally common among those who have had an anal abscess. Treatment is usually necessary to reduce the chances of infection in an anal fistula, as well to alleviate symptoms. An anal fistula is defined as a small tunnel with an internal opening in the anal canal and an external opening in the skin near the anus. Anal fistulas form when an anal abscess, that's drained, doesn't heal completely. Different types of anal fistulas are classified by their location.