An anorectal abscess is a collection of pus in the anal or rectal region.

Infection of an anal fissure, sexually transmitted infections, and blocked anal glands are common causes of anorectal abscesses. Deep rectal abscesses may be caused by intestinal disorders such as Crohn's disease or diverticulitis.

The following factors increase your risk for an anorectal abscess:

• Diabetes
• A weakened immune system
• Engaging in anal sex
• Inflammatory bowel disease (Crohn's disease and ulcerative colitis)

The condition may occur in infants and toddlers who are still in diapers and who have a history of anal fissures. The abscess often appears as a swollen, red, tender lump at the edge of the anus. The infant may be fussy from discomfort, but there are generally no other symptoms.

• Painful, hardened tissue in the perianal area
• Discharge of pus from the rectum
• Lump or nodule, swollen, red, tender at edge of anus
• Fever
• Pain associated with bowel movements
• Constipation (may occur)

A rectal examination may confirm that you have an anorectal abscess. A proctosigmoidoscopy may be done to rule out other diseases.