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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.

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Causes  

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  

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
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Symptoms  

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