Anal Sac Disease in Cats

What are anal sacs?

Cats have two small anal sacs, one on each side of the anus at roughly the four o’clock and eight o’clock positions, just under the skin. Each sac empties through a small duct and stores a strong-smelling fluid that is normally released in tiny amounts when the cat passes stool. The scent is a form of territorial marking.

Anal sac problems are less common in cats than in dogs, but they do occur, and because cats hide discomfort well they are often further along by the time they are noticed.

What kinds of problems can occur in the anal sacs?

The same three problems seen in dogs occur in cats:

• Impaction: the fluid thickens and cannot drain, so the sac becomes full and uncomfortable.
• Infection (sacculitis): bacteria multiply in the trapped fluid, producing yellow or bloody discharge.
• Abscess: infection builds into a hot, painful swelling beside the anus. If it ruptures, the skin breaks open and pus drains onto the coat.

Soft stools, diarrhea, obesity, and a sedentary indoor lifestyle all make impaction more likely because the sacs are not being emptied normally.

How will I know if my cat is having problems with the anal sacs?

Signs of anal sac disease in cats include:

• Scooting or dragging the rear end along the floor
• Excessive licking or chewing under the tail, sometimes with hair loss in that area
• Straining or crying when passing stool, or avoiding the litter box
• A swelling or open, draining sore on one side of the anus
• A sudden strong, fishy odor
• Irritability or resentment of being handled near the tail

Because several of these signs overlap with constipation, urinary problems, and parasites, an examination is the only way to tell them apart.

How are the various anal sac diseases treated?

Impaction is treated by gently expressing the sacs to clear the thickened material. Infection also requires expression, followed by antibiotics and sometimes an anti-inflammatory for comfort. An abscess is lanced or opened, flushed, and treated with antibiotics; a ruptured abscess needs the wound cleaned and kept open to drain while it heals. An Elizabethan collar may be needed for a few days to stop licking.

My cat has had several bouts of anal sac disease. Is there a long-term cure?

Most cats have a single episode and never another. For the few that have repeated problems, we look first for an underlying cause such as chronic soft stool, food sensitivity, or excess weight, since correcting that usually stops the cycle. Adding fiber to the diet can help the stool empty the sacs naturally. When episodes continue despite this, the anal sacs can be surgically removed (anal sacculectomy). Cats do not need these sacs, and removal is a permanent cure.

Are there any complications with the surgery?

Surgery requires general anesthesia, which always carries some degree of risk, though modern anesthetics keep that risk very low for an otherwise healthy cat. The nerves that control the anus run close to the sacs, so a small number of cats have temporary difficulty controlling their stool after surgery. This almost always resolves within days to a couple of weeks.

Can I prevent anal sac problems?

Keeping your cat at a healthy weight, feeding a diet that produces firm stools, and encouraging play and activity all help the sacs empty on their own. Routine expression is not recommended for cats without a history of problems, as it can irritate the ducts. If you notice scooting, licking, or swelling near the tail, call us the same day; an impaction caught early is a quick, minor procedure, while an abscess is painful and takes longer to heal.

See also: Anal Sac Disease in Dogs