What are the causes for Anal Abscess?

Perirectal and perianal abscesses are thought to develop from the glands surrounding the anus; on occasion, perianal abscesses may develop from infected skin adjacent to the anus. Glands may plug up, usually leading to bacterial infection. When the glands 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 conditions:
  • Diabetes
  • AIDS or HIV infection with low white blood cell counts
  • Crohn's disease
  • Persons on medications that suppress the body's immune system, such as steroids (prednisone, methylprednisolone), or those undergoing chemotherapy for cancer
  • Pregnancy
  • Placement of foreign bodies into the anus
  • Sexually transmitted diseases
  • anal fissures

    Source: http://www.emedicinehealth.com