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Anal Abscess/Fistula

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There are small glands just inside your anus. If one of these glands becomes blocked, it can become infected. This infected gland is called an abscess. A fistula forms when a tunnel is formed that connects the infected gland to an opening on the skin around the anus.


Constant pain, sometimes accompanied by swelling, is a symptom of an anal abscess. The pain is not necessarily related to a bowel movement.

Other symptoms of an abscess or fistula are:

  • Pain with bowel movements
  • Bleeding
  • Drainage of pus or blood which may alleviate the pain
  • Irritation or a “sore spot” on your skin from the drainage
  • Fever, chills, and a general feeling of fatigue due to the infection

Causes and Risk Factors

An abscess occurs when bacteria or foreign matter get into the tissue through a gland. Half of all abscesses will develop a fistula.

Known risk factors include:

  • Colitis, Crohn’s disease or other inflammation of the intestine
  • Sexually transmitted diseases
  • Trauma
  • Tuberculosis
  • Cancer
  • Diverticulitis

Diagnostic Tests

You should talk to your doctor if you are experiencing any of the symptoms of an anal abscess or fistula. Your doctor will start with a complete medical history to determine the frequency and duration of your symptoms.

Other tests include:

  • Physical exam of the affected area
  • Blood tests
  • X-ray
  • Colonoscopy
  • Anoscopy if the affected area is not close to the surface
  • Ultrasound to better locate the abscess
  • MRI to better define the fistula tract

Treatment and Procedures

Abscesses can typically be treated in your doctor’s office where they can be drained using a local anesthetic. Larger abscesses and fistulae might require more intense treatment including:

  • Surgical drainage of the abscess and repair of the fistula
  • Antibiotic treatment
  • Placement of a steton if continual drainage is needed

Even if the abscess drains on its own, you should be evaluated and treated by a doctor specializing in treating anal abscesses.

Your health is our greatest concern. Please contact the Center for Colon & Rectal Surgery at 407.303.2615for a private consultation today.