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. Normal anatomy includes small glands just inside the anus. Anal Fistula: Diagnosis and TestsAnal Fistula (Child) A fistula is a passage between a hollow or tubular opening and another body tissue or between 2 tubular organs. Fistulas may form different locations and variations in the body, but anorectal fistulas are the most common. Surgery may be necessary to correct a fistula, but certain lifestyle changes may make a difference, too. To heal a fistula, avoid eating spicy food, junk food, or fatty food, which can upset your stomach and make your fistula worse. Perianal Fistula in Cats - Treatment and CareThis condition is most likely to occur in German Shepherds, though it can happen in any breed. Perianal fistulas can cause a great deal of pain and discomfort in your dog. Dogs that experience a perianal fistula may also have chronic diarrhea as a result of inflammatory bowel disease; it is thought that these two conditions may be connected. Perianal fistula, which is also known as anal furunculosis, occurs when a dog experiences chronic lesions around their anus that worsen, leading to deep ulcers that drain and are painful to the dog. An anal, or rectal, abscess occurs when a cavity in the anus becomes filled with pus. It causes extreme pain, fatigue , rectal discharge, and fever. In some cases, anal abscesses can result in painful anal fistulas. A blocked anal gland, a sexually transmitted infection STI , or an infected anal fissure can cause anal abscesses.