WHAT IS AN ANAL ABSCESS OR FISTULA?

An anal abscess is an infected cavity filled with pus found near the anus or rectum. Ninety percent of abscesses are the result of an acute infection in the internal glands of the anus. Occasionally, bacteria, fecal material or foreign matter can clog an anal gland and tunnel into the tissue around the anus or rectum, where it may then collect in a cavity called an abscess.

An anal fistula (also commonly called fistula-in-ano) is frequently the result of a previous or current anal abscess. This occurs in up to 50% of patients with abscesses. Normal anatomy includes small glands just inside the anus. The fistula is the tunnel that forms under the skin and connects the clogged infected glands to an abscess. A fistula can be present with or without an abscess and may connect just to the skin of the buttocks near the anal opening.

Symptoms of anal fistulas

Possible symptoms include:

• Pain, which is usually constant, throbbing and worse when sitting down
• Skin irritation around the anus, including swelling, redness and tenderness
• Discharge of pus or blood
• Constipation or pain associated with bowel movements
• Fever