Anal Fistula

The anal canal is the end portion of the intestinal tract. It is a channel or tunnel that connects the rectum to the anus. Sometimes, an abnormal passage forms from the anal canal to the skin near the anus. This is called an anal fistula. Anal fistulas can also form from the anal canal to other organs, such as the vagina or urinary tract.

An anal fistula most often occurs from an anal gland that has developed a pus-filled infection (abscess). A fistula can also occur with certain conditions. These include Crohn’s disease or after radiation therapy for cancer in the pelvic area, such as rectal cancer. Injury to the anal canal and surgery can also lead to anal fistulas. Some sexually transmitted infections (STIs), like herpes and gonorrhea, can also raise the risk of anal fistulas.

Symptoms of an anal fistula can include:

• Itching

• Discomfort or pain while passing stools

• Pain in or near the rectum

• Drainage, which may contain blood, pus, or both (the drainage may be constant or stop and start again)

• Bleeding from the rectum

• Fever

• Urinary problems

If you have an anal abscess or infection along with a fistula, you may also notice redness, swelling, or soreness in or near the anus or rectum.

Treatment often depends on the location, severity, and cause of the anal fistula. The abscess usually needs to be drained.

If caused by Crohn’s disease, an anal fistula may respond to medicines such as antibiotics and immunosuppressants. This may lead to complete closure of the fistula. But once treatment stops, there is a high chance that the fistula may form again.

Anal fistulas often require surgery if other treatments don’t correct the problem. The type of surgery depends on the type of fistula and the cause of the fistula. More than 1 surgery may be needed.

If you have questions about treatment, your healthcare provider can help.