Anal Abscess

(Anal Rectal Abscess; Anorectal Abscess)

Definition

An anal abscess is a pus-filled pocket located in the spaces around the anus and rectum. An abscess can be found near the surface of the anal opening or deeper in the rectum.

Causes    TOP

An anal abscess is caused by a bacterial infection. Infection may occur when there is a blockage in one or more of the anal glands that secrete mucous or fistula tract in the anus or rectum.

Anal Abscess

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Risk Factors    TOP

Anal absesses are more common in men. Other factors that may increase your chance of developing an anal abscess include:

  • Certain conditions, such as Crohn's disease, ulcerative colitis, or sexually transmitted diseases
  • Receptive anal intercourse
  • Medications that suppress the immune system
  • Pregnancy

Symptoms    TOP

Symptoms depend on where the abscess is located. An anal abscess may cause:

  • Pain and tenderness radiating from the location of the abscess if it is near the surface
  • Lower abdominal pain if it is located deeper in the rectum
  • Redness and swelling—visible with a surface abscess; also occurs in a deep abscess, but cannot be seen
  • Pus drainage
  • Fever

Complications of an anal abscess may include:

  • Anal fistula—abnormal channel between the rectum and the surface of the anal skin leading to the outside
  • Systemic sepsis—serious, life-threatening infection that spreads throughout the body
  • Stool incontinence

Diagnosis    TOP

Your doctor will ask about your symptoms and medical history. A physical exam will be done. An abscess near the surface of the skin may be visible. A deeper abcsess may require a digital rectal exam. The doctor will feel the inside of your anal canal for any abnormalities.

Imaging tests to look at anorectal structures may include:

Treatment    TOP

Surgical drainage is necessary to treat an anal abscess. The type of procedure depends on the location and depth of the abscess. It is possible that you may have a drain in the wound for up to three weeks to help the healing process.

Medications

Antibiotics are generally not necessary, but your doctor may recommend them under certain circumstances. Other medications may include:

  • Over-the-counter or prescription pain medication
  • Stool softeners, fiber, or bulk laxatives

Prevention    TOP

To reduce your chance of developing an anal abscess, be sure to manage any health conditions that increase your risk of infections.

RESOURCES:

American College of Gastroenterology
http://gi.org
American Society of Colon and Rectal Surgeons
http://www.fascrs.org

CANADIAN RESOURCES:

Canadian Association of Gastroenterology
http://www.cag-acg.org

References:

Abcarian H. Anorectal infection: Abscess-fistula. Clin Colon Rect Surg. 2011;24(1):14-21.
Anal abscess/fistula. American Society of Colon and Rectal Surgeons website. Available at:
...(Click grey area to select URL)
Updated October 2012. Accessed November 14, 2013.
Anal rectal abscess and fistula. Hemorrhoid website. Available at:
...(Click grey area to select URL)
Accessed November 14, 2013.
Anorectal abscess. John Hopkins Medicine website. Available at:
...(Click grey area to select URL)
Accessed November 14, 2013.
Caliste X, Nazir S, et al. Sensitivity of computed tomography in detection of perirectal abscess. Am Surg. 2011;77(2):166-168.
Schaffzin DM, Wong WD. Surgeon-performed ultrasound: endorectal ultrasound. Surg Clin North Am. 2004;84(4):1127-1149, vii.
Last reviewed November 2013 by Michael Woods, MD
Last Updated: 11/14/2013