The most common cause of an anorectal fistula is an infection or abscess in the anal area. Other possible causes of an anorectal fistula include trauma, inflammatory bowel diseases, radiation therapy, and previous surgery.
Infection or Abscess
An infection or abscess in the anal area is the most common cause of an anorectal fistula. An abscess is an infection in the anal area that is filled with pus. An abscess can form when bacteria enters the tissue through a cut or tear in the skin. The infection can spread to the deeper layers of the skin, causing an abscess to form. The infection can then tunnel through the tissue to create a fistula.
Trauma
Trauma to the anal area can also lead to an anorectal fistula. Trauma can include any sort of injury or damage to the area, such as a burn, an anal fissure, or a cut or tear in the skin.
Inflammatory Bowel Diseases
Inflammatory bowel diseases such as Crohn's disease and ulcerative colitis can also lead to an anorectal fistula. These diseases are characterized by inflammation and ulceration of the intestinal lining, which can lead to an infection or abscess and can eventually result in a fistula.
Radiation Therapy
Radiation therapy, typically used to treat cancer, can also lead to an anorectal fistula. Radiation therapy can cause damage to the tissues in the anal area, leading to an infection or abscess and eventually a fistula.
Previous Surgery
Previous surgery in the anal area is another possible cause of an anorectal fistula. Surgery can damage the tissue in the area, leading to an infection or abscess and eventually a fistula.