Symptoms and Treatments of Anal Sac Disease in Dogs

The dog has two anal sacs or glands located at five and seven o'clock in reference to the circumference of the anus. They can be seen by drawing down on the skin of the lower part of the anus and looking in those locations.

The anal sacs are similar to scent glands. In skunks they serve a defensive purpose. In dogs they produce an odor that identifies the individual and marks his stool to establish territory. This is why dogs greet each other by sniffing at the rear.

The anal sacs are emptied by the pressure of stool passing through the anus. They can also be emptied by forceful contractions of the anal sphincter-something that may happen when a dog is frightened or upset.

Anal sac disease is a cycle that begins with impaction and progresses through infection to abscess and rupture. Dogs with anal problems may develop tonsillitis from licking at the rear area.

Anal Sac Impaction

Impaction is the accumulation of pasty secretions in the anal sacs. The sacs become distended and mildly tender. The expressed secretions are thick and dark brown or grayish brown. The sacs become impacted when they don't empty completely. This may be due to insufficient pressure on the sacs during defecation because of small, soft stools; inadequate sphincter pressure; or blockage of the openings by thick, dry secretions. Impactions tend to occur most often in small-breed dogs and in overweight dogs.

Treatment: Impaction is treated by manually expressing the secretions. Dogs with recurrent anal sac impactions should have their sacs emptied at regular intervals. Place the dog on a high-fiber diet or a bulk laxative to increase the size of the stools (see

How to Empty the Anal Sacs

Manually emptying the anal sacs is called expressing them. It is not necessary to express the anal sacs unless the dog has an anal sac disease, or when frequent malodor poses a problem. Begin by putting on a disposable latex or plastic surgical glove. Raise the dog's tail and locate the openings as shown in the figure on this page. If they're full, the anal sacs can be felt as small, firm lumps in the perianal area at the five and seven o'clock positions.

Grasp the skin surrounding the sacs between your thumb and forefinger and squeeze. When an anal sac is impacted (blocked), it usually is best to empty the sacs with a finger in the anal canal and a thumb on the outside.

As the sac empties, you may smell a strong odor. Wipe the secretions with a damp cloth or gently hose the dog's rectal area. Normal secretions are liquid and brown. If the discharge is yellow, bloody, or puslike, the sac is infected and you should seek veterinary attention.