What is an Anal Abscess and an Anal Fistula?

What is an Anal Abscess?

An anal abscess is an infected cavity filled with puss near the anus or rectum.

What Causes an Anal Abscess?

An anal abscess is almost always the result of an acute infection of a small gland just inside the anus. Bacteria or other foreign matter enters the tissue through the gland. Certain conditions such as colitis, or inflammation of the intestine can be a cause of an abscess. Also, the cause can be a sexually transmitted infection from anal sex.

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Who is at Risk for Anal Abscess?

Infants and toddlers who are still in diapers and who have a history of anal fissures can develop anal abscesses.  Some people are more at risk for developing an anal abscess based on the following factors:

  • Having anal sex
  • Taking certain medications like prednisone or chemotherapy treatments
  • A weakened immune system – HIV/AIDS
  • Inflammatory Bowel Disease – Crohn’s, Ulcerative Colitis

What are Some Symptoms of Anal Abscess?

  • Pain and swelling around the anus
  • Fatigue
  • Fever or chills
  • Severe pain with bowel movements
  • Constipation
  • Pus from the rectum
  • A tender lump at the edge of the anus

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How is an Abscess Treated?

First the pus is drained through a small incision in the skin near the anus to relieve the pressure. This can often be done in the doctor’s office with a local anesthetic. Large or deep abscesses may require hospitalization. Those who are diabetic or have impaired immune systems also may require treatment in the hospital. Antibiotics are not effective.

What is an Anal Fistula?

An anal  fistula is a small tunnel that forms under the skin that connects a previously infected anal gland to the skin in the buttocks outside the anus. A fistula can be present with or without an abscess.

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What Causes a Fistula?

A fistula occurs when an abscess has been drained, but the tunnel persists. In this case there may be continued drainage from the outside opening. If the outside opening heals, a recurrent abscess may develop.

What are the Symptoms of an Anal Fistula?

Symptoms of a fistula include irritation of the skin around the anus, drainage of pus (which will bring relief from the pain), fever and just not feeling well.

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How is a Fistula Treated?

Fistulas are treated with surgery and may be performed along with the abscess surgery. However, fistulas often develop several weeks or longer after an abscess is drained. Surgery usually involves opening the fistula tunnel and possibly cutting a small part of the anal sphincter muscle that helps control bowel movements. It heals from the inside out. This is typically done on an outpatient basis, although some cases may require a short stay in the hospital.

Recovery for Anal Abscess and Fistula

Discomfort usually occurs for a week and pain pills are given to relieve pain. A few days at home taking sitz baths (sitting in a few inches of warm water) three or four times a day are recommended. Stool softeners may also be recommended. Bowel movements do not affect healing.

Do Abscesses or Fistulas Recur?

With proper healing they generally do not. Follow your doctor’s instructions following treatment to insure the best results.
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Dr. Abbadessa is board certified by the AOA and is a member of the Missouri Association Osteopathic Physicians and Surgeons
| St. Louis Metropolitan
Medical Society | Missouri State Medical Association

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