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Anal Sac Disease in Dogs

The anal sacs are located on either side of the anus at the 9 o’clock and 3 o’clock positions; they are positioned just under the skin. They connect to the anus by means of small canal or ducts. Anal sacs produce and store a dark, foul-smelling fluid. These are the same types of organs that a skunk has to scare away its enemies. Although dogs can use these for the same purpose, most dogs live in an environment that has no enemies. Because the sacs are rarely emptied, the fluid builds up, solidifies, and becomes an ideal environment in which bacteria can grow.

The Three Diseases

There are 3 diseases that occur in the anal sacs.

  1. When the fluid becomes thick and solidified, the condition is called impaction.
  2. When bacteria grow in this material producing a yellow or bloody pus, the condition is called infection.
  3. When the infection builds to create a hot, tender swelling in the gland, the condition is called an abscess. When the abscessed material overflows the sac, the skin over the sac breaks open, and the pus drains onto the skin.

Clinical Signs

Symptoms of anal sac disease are:

  1. Scooting or dragging the anal area.
  2. Excessive licking under the tail.
  3. Pain, sometimes severe, near the tail or anus.
  4. A swollen area on either side of the anus.
  5. Bloody or sticky drainage on either side of the anus.


The treatment for impaction is to express the sacs and clean out the solidified material. For infection, the sacs must be expressed and antibiotics administered to kill the bacteria. If the sacs abscess, the abscess must be surgically drained and antibiotics administered.

Treatment for Dogs with Recurrent Disease

Many dogs have recurrent anal sac disease. Some breeds of dogs, such as Poodles, commonly have problems. The anal sacs of obese dogs do not drain well, and thus these dogs are predisposed to recurrent problems. If a dog has several episodes of anal sac disease, the anal sacs can be removed surgically. Because these sacs are virtually unused, there is no loss to the dog. It is the only way to permanently cure the problem.

Complications of the Surgery

Surgery requires general anesthesia that always carries some degree of risk, whether the patient is a dog or a person. However, modern anesthetics make this risk very minimal for dogs that are otherwise healthy.

Some dogs will experience lack of good bowel control. They may drop fecal balls as they walk. This occurs because the nerves that control the anus are very near the anal sacs and may be damaged during surgery. However, this is almost always a temporary problem that will resolve itself in a few days to a couple of weeks.

Leaking Anal Sacs

Some dogs are born with anal canals that do not close well. These dogs are constantly draining anal sac fluid and leaving a foul-smelling drop whereever they have been. This is another indication for anal sac removal. There does not appear to be any other way to stop this, and these dogs do not outgrow this problem.