Anal fistula


An anal fistula is an inflammatory tract between the anal canal and skin. It is fairly common in people who have had an anal abscess. Usual signs and symptoms include pain, discharge, either bloody or purulent, pruritus ani, fatigue, irritation of skin around the anus and visible redness and swelling. If fistula becomes infected, the patient may has fever and chills. Physical examination of the area is a usual diagnosis method of a fistula. Treatment of anal fistula often varies, depending on whether Crohn’s disease is present, whether the patient has active infection. It includes medication and surgery. Many patients with fistula have a good prognosis after surgery.

What are the symptoms?

Patients with anal fistula may experience the following symptoms:

  • Pain
  • Discharge, either bloody or purulent
  • Pruritus ani or itching
  • Fatigue
  • Irritation of skin around the anus
  • Visible redness and swelling
  • If fistula becomes infected, fever and chills

Other health problems may also cause these symptoms. Only a doctor can tell for sure. A person with any of these symptoms should tell the doctor so that the problems can be diagnosed and treated as early as possible.

Who is at highest risk?

The following factors increase your chance of developing an anal fistula. If you have any of these risk factors, discuss them with your doctor:

  • Colitis or other inflammatory bowel disease, for example Crohn’s disease
  • Passage of hard stool
  • Chronic diarrhea


  • Physical examination: Diagnosis of a fistula is usually made on examination of the area. If it is near the anus, the physician will look for an opening in the skin (a sign that a fistula has developed), and try to determine the depth and direction of the channel or tract of the fistula.
  • Anoscope: If signs of fistula may not be present on the skin’s surface around the anus, the doctor uses an instrument called an anoscope to see inside the anal canal and lower rectum.
  • Blood tests, x-rays, and a colonoscopy: Whenever the physician finds a fistula, further tests such as blood tests, x-rays, and a colonoscopy are needed to be sure Crohn’s disease is not present.

Diseases with similar symptoms

  • Inflammatory bowel disease, such as Crohn’s disease
  • Syphilis
  • Herpes simplex

When to seek urgent medical care?

Call your health care provider if symptoms of anal fistula develop. If you experience either of the following symptoms, seeking urgent medical care as soon as possible:

  • Discharge a lot of blood.
  • Fever and chills

Treatment options

Treatment of anal fistula often varies, depending on whether Crohn’s disease is present, whether the patient has active infection. It includes medication and surgery.

  • If Crohn’s disease is present, a variety of medications including antibiotics is usually undertaken. Often these medications will cure the infection and heal the fistula.
  • If Crohn’s disease is not present, it may still be worthwhile to try a course of antibiotics.
  • If antibiotics do not work, surgery is usually very effective. The surgeon opens the fistula channel so that the fistula can be healed from the inside out. Generally, the surgery is done on an outpatient basis or with a short hospital stay.
  • If the patient has active infection, this requires clearing up before definitive treatment can be decided. A seton is the best choice. It is a length of suture material looped through the fistula which can keep it open and allows pus to drain out.

Where to find medical care for Anal fistula?

Ask our experts on anal fistula


There are no known ways to prevent anal fistula because the cause of the original infection of anal glands is unknown.

What to expect (Outlook/Prognosis)?

Prognosis for fistulas is excellent after surgery.

Possible complications

Complications from an anal fistula are usually the result of fistula surgery, this may be an infection, incontinence or even recurrence of the anal fistula.



This article incorporates public domain material from Wikidoc and MedlinePlus. Please see licenses for further details.

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