An anal fistula is an abnormal channel connecting the inside of the anal canal with the skin around the anus.
In most cases, it is the result of an abscess that develops for unknown reasons in the wall of the anus and does not heal properly. An anal fistula may also sometimes develop as a result of an intestinal disorder such as Crohn’s disease , ulcerative colitis , or colon cancer.
Symptoms of an anal fistula may include a discharge of pus onto the skin around the anus; passing blood or pus in the feces; irritation, swelling, redness, and constant, throbbing pain around the anus; and, in some cases, fever and fecal incontinence.
A fistula rarely heals by itself and usually requires treatment with surgery.
