Anal Abscess (and Anal Fistula)
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Anal Abscess (and Anal Fistula)

(Anal Rectal Abscess; Anorectal Abscess; Anal Rectal Fistula; Anorectal Fistula)

En Español (Spanish Version)


An anal abscess is a pus-filled glandular cavity near the anus, either deep in the rectum or close to the anus opening. Eight to nine people out of 10,000 will experience this condition.


Abscesses result when bacteria infect a mucus-secreting gland in the anus or rectum, causing blockage and damage to surrounding intramuscular tissue. The reason why the infection occurs is unknown because, normally, this area is free from infection.

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition.

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


If you experience any of these symptoms do not assume it is due to an anal abscess. These symptoms may be caused by other health conditions. If you experience any one of them, discuss them with your doctor.

Symptoms include:

In the case of an abscess near the surface of the skin on the buttocks:

  • Pain and tenderness radiating from the location of the abscess
  • Visible redness and swelling
  • Fever

In the case of an abscess located deeper within the rectum:

  • Pain in the lower abdomen
  • Swelling in the rectum that can be seen during examination of the rectum
  • Fever

Anal abscesses may be accompanied by pain with stool and/or stool incontinence (inability to restrain stools).


Your doctor will ask about your symptoms and medical history, and perform a physical exam. While your doctor will be able to see an abscess near the surface of the skin, he or she may need to exam the rectum with a gloved finger to determine the presence of a deeper abscess.


Treatment normally consists of draining the abscess, which is done by making an incision through the skin near the anus into the abscess. For this, you will be given local anesthesia. In rare cases, admittance to a hospital is required, as well as general anesthesia . Antibiotics may be given to reduce fever or under other special circumstances.

Complications of Treatment

Following drainage (or natural rupture) of an abscess, more than half the cases will develop into anal fistulas—usually occurring weeks but sometimes years later. In this condition, a permanent abnormal channel is formed from the site of the original abscess to the surface of the skin near the anus. This channel (fistula) allows for the continuous drainage of the abscesses’ pus-like fluid. In the case of a fistula, surgery to remove and close-up the channel is normally recommended. Following surgery, recurrence of a fistula is common, and stool incontinence may occur.

Anal Fistula

anal fistula

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There are no known ways to prevent anal abscesses or subsequent fistulas because the cause of the original infection of anal glands is unknown.


American College of Gastroenterology

American Society of Colon and Rectal Surgeons


Canadian Association of Gastroenterology

Capital Health


Anal abscess/fistula. American Society of Colon and Rectal Surgeons website. Available at: Accessed November 25, 2006.

Anal rectal abscess and fistula. website. Available at: . Accessed Nov. 29, 2006 .

Anorectal abscess. The Merck Manuals Online Medical Library website. Available at: Accessed November 28, 2006.

Common gastrointestinal problems: rectal complaints. American College of Gastroenterology website. Available at: . Accessed Nov. 28, 2006 .

Fistual-in-ano. DynaMed website. Available at: Accessed November 25, 2006.

Legall I. Anal fistulas and fissures. Emedicine website. Available at: . Accessed Nov. 27, 2006.

Last reviewed February 2008 by David Mahnke, MD

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.

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