Anal Abscess Causes

Perirectal and perianal abscesses are thought to develop from the glands surrounding the anus. These glands may plug up, leading to infection. When they fill with pus, they may burst inward, releasing their infected contents into the spaces around the rectum and anus. This pus causes an abscess, or pus collection, in the spaces surrounding the rectum or anus. The anal abscess may enlarge, causing pain, fever, and difficulty with bowel movements.

Certain people are more likely to develop perirectal and perianal abscesses, including those with the following medical problems:

• Diabetes

• AIDS or HIV infection with low white blood cell counts

• Crohn disease

• Persons on medications that suppress the body's immune system, such as steroids (prednisone, methylprednisolone), or those undergoing chemotherapy for cancer