How common are anal fistulae?
Anal fistulae are more common in men, and occur between 20 and 40 years of age. A study that was published in 2007 and looked at four different European countries, found that there are between one and three cases of anal fistulae for every 10,000 people. An anal fistula usually develops after an anal abscess (a collection of pus) bursts, or where an abscess has not been completely treated. A fistula can also be caused by a condition that affects the intestines, such as irritable bowel syndrome (IBS) or Crohn’s disease. Among people with Crohn’s disease, the incidence of anal fistulae may be as high as 30-50%. Up to 30% of people with HIV (a virus that attacks the body’s immune system) will also develop an anal fistula.
