Anorectal Abscess


The last phase of the digestive process is the collection of and passing from the body of solid wastes. These wastes (what's left of what we eat after the water and nutrients have been taken by our bodies) collect in the rectum and then are expelled through the anus. The inside of the anus is lined with glands and four to six crypts or pockets. Sometimes one of these pockets gets filled with stool. This can cause the gland to become infected and develop an abscess.


Signs of an anorectal abscess include:

  • Fever
  • A vague feeling of being unwell or uncomfortable
  • Swelling and discomfort around or near the anus
  • Redness around the area
  • Drainage of pus or fluid from the area

Causes and Risk Factors

This type of abscess is usually happens when the glands in the area of the anus or rectum become infected. When an infection occurs in a gland, it can create a cavity that fills with pus. The cavity swells and causes constant pain and discomfort. The skin may look red and swollen and drain pus.


A doctor will take the patient's medical history and do a physical examination. Diagnosis will be based on the symptoms and the presence of pain or tenderness, swelling, redness and possible drainage of pus from the area.

The presence of a fever or an elevated white blood cell count as measured by a blood test can confirm the presence of an infection in the body.


Antibiotics alone are rarely enough to treat this type of infection. Usually surgical drainage is required.

In about half the cases where an abscess has drained, a fistula (an opening between the inside of an anal pocket or gland where the infection started and the outside of the body where it drained) can develop. 

A fistula will not heal without treatment that involves removing the pocket where the infection started.

© 2000-2022 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.
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