Anal Abscess


An anal abscess is an infected cavity filled with pus found near the anus or rectum.

What causes an abscess?
Most abscesses result from an acute infection of a small gland just inside the anus.  Less frequent abscesses occur from an infection from an anal fissure or from sexually transmitted disease (STD).   Deep abscesses may be caused from Crohn’s disease or diverticulitis.

What are the Risk Factors for developing an anal abscess?
Some of the risk factors for developing an anal abscess are:

  • Diabetes
  • Chemotherapy drugs used to treat cancer
  • Inflammatory Bowel Disease such as Crohn’s or Ulcerative colitis
  • Anal Sex
  • Weakened Immune System

What are the symptoms of an abscess?
Symptoms of an anal abscess include:

  • Pain
  • Swelling
  • Redness
  • Fever
  • Feeling poorly
  • Sometimes spontaneous drainage of pus. The pus can be bloody.

How is an anal abscess diagnosed?
An in-office examination by a colon and rectal surgeon will generally allow proper diagnosis of an anal abscess.  On occasion, additional imaging studies may be ordered to assist in the diagnosis of a complex or deep abscess.

What is the treatment of an anal abscess?
The treatment of an abscess is surgical drainage under most circumstances.  Antibiotics alone usually cannot treat the problem.  If it is a superficial abscess, it can be drained in the doctor’s office with local anesthesia.  If the abscess is more complex and deeper, it may require drainage in the operating room.

What is the prognosis after treatment?
Approximately one-third of all anal abscesses will resolve and not recur; one-third will appear to resolve, but then a recurrent abscess will occur in the future at the same location; in one-third of the patients the wound will not heal completely and a low level of persistent drainage will be noted.  The latter two events are consistent with an anal fistula.