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Ano-rectal Abscess/Anal Fistula


An anal abscess is a pus-filled pocket around the anus and rectum. It may be near the surface of the anal opening or deeper in the rectum.

If left untreated, it can lead to an anal fistula or infection.


An anal abscess is caused by a bacterial infection. It may happen when there is a blockage in one or more of the anal glands. Or it may be from a tear in the anal tissue (fissure).

The Anus
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Risk Factors

Anal abscesses are more common in men. Other things that may raise the risk are:

  • Certain health problems, such as Crohn disease , ulcerative colitis, or sexually transmitted infections
  • Medicines that suppress the immune system
  • Pregnancy
  • Anal intercourse
  • Diabetes


Symptoms depend on where the anal abscess is located. Problems may be:

  • Painful bowel movements
  • Pain and tenderness—from an abscess that is near the surface
  • Lower belly pain—from an abscess that is deeper in the rectum
  • Redness and swelling of an abscess that is near the surface
  • Drainage
  • Fever


The doctor will ask about symptoms and past health. A physical exam will be done. An abscess near the surface of the skin may be seen during the exam. The doctor may also do a digital (finger) exam of the rectum. This is often enough to diagnose an anal abscess.

Imaging tests are not usually needed, but may include:


An anal abscess needs to be treated right away. This usually involves making an incision in the anus and draining the abscess. This may be done in the doctor's office or in the hospital. The type of procedure depends on its location and depth.

Medicines may also be needed to:

  • Ease pain and swelling
  • Prevent infection


The risk of an anal abscess can be lowered by managing health problems that raise the risk of infection.


  • Abscess and fistula expanded information. American Society of Colon and Rectal Surgeons website. Available at: https://fascrs.org/patients/diseases-and-conditions/a-z/abscess-and-fistula-expanded-information.
  • Anorectal abscess. Johns Hopkins Medicine website. Available at: https://www.hopkinsmedicine.org/health/conditions-and-diseases/anorectal-abscess.
  • Cohee MW, Hurff A, et al. Benign anorectal conditions: evaluation and management. Am Fam Physician. 2020;101(1):24-33.
  • Fistula in ano and anorectal abscess. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/fistula-in-ano-and-anorectal-abscess.
  • Vogel JD, Johnson EK, et al. Clinical Practice Guideline for the Management of Anorectal Abscess, Fistula-in-Ano, and Rectovaginal Fistula. Dis Colon Rectum. 2016;59(12):1117-1133.