Anal Sac Disease in Dogs

What are the anal sacs?

Commonly called 'anal glands', the anal sacs are two small pouches located on either side of the anus at approximately the four o'clock and eight o'clock positions. Numerous specialized sebaceous (sweat) glands that produce a foul smelling secretion line the walls of the sacs. Each sac is connected to the outside by a small duct that opens just inside the anus.

What is their function?

The secretion acts as a territorial marker - a dog's 'calling card'. The sacs are present in both male and female dogs and some of the secretion is squeezed out onto the feces by muscular contractions when the dog defecates. This is why dogs are so interested in smelling one another's feces.

Why are the anal sacs causing a problem in my dog?

Anal sac disease is very common in dogs. The sacs frequently become impacted, usually due to inflammation of the ducts. The secretion within the impacted sacs will thicken and the sacs will become swollen and distended. It is then painful for your dog to pass feces. The secreted material within the anal sacs is an ideal medium for bacterial growth, allowing abscesses to form. The abscess will appear as a painful, red, hot swelling on one or both sides of the anus. If the abscess bursts, it will release a quantity of greenish yellow or bloody pus. If left untreated, the infection can quickly spread and cause severe damage to the anus and rectum.

 How will I know if my dog has anal sac problems?

"The first sign is often scooting or dragging the rear along the ground."

The first sign is often scooting or dragging the rear along the ground. There may be excessive licking or biting, often at the root of the tail rather than the anal area. Anal sac disease is very painful. Even normally gentle dogs may snap or growl if you touch the tail or anus when they have anal sac disease. If the anal sac ruptures, you may see blood or pus draining from the rectum.

In some cases, the dog had an episode of diarrhea or digestive upset a week or two before the clinical signs of anal sac disease became evident.

How is anal sac disease treated?

Problems with the anal sacs are common in all dogs, regardless of size or breed. If you are concerned that your pet may have an anal sac problem, call your veterinarian at once.  Treatment for impaction involves expressing or emptying the sacs. If the impaction is severe or if there is an infection, it may be necessary to flush out the affected sac to remove the solidified material. Since these conditions are painful, many pets will require a sedative or an anesthetic for this treatment. Antibiotics are often prescribed and sometimes may need to be instilled into the sacs over a period of several days. In advanced or severe cases, surgery may be necessary. Most dogs will require pain relief medications for several days until the swelling and inflammation have subsided.

Is the condition likely to recur?

Some dogs will have recurrent anal sac impactions or abscesses.

"Overweight dogs tend to have chronic anal sac problems because their anal sacs do not empty well."

Overweight dogs tend to have chronic anal sac problems because their anal sacs do not empty well. Each impaction may cause further scarring and narrowing of the ducts, leading to recurrences that are even more frequent. If this condition recurs frequently, surgical removal of the sacs is indicated.

My dog is very nervous and sometimes seems to express his own glands. Is this normal?

"It is common for dogs to release the contents of their anal sacs, particularly if frightened."

It is common for dogs to release the contents of their anal sacs, particularly if frightened. Some dogs even appear to lack control of the anus or anal sac ducts so that small quantities of fluid will drain out when they are resting, leaving an unpleasant lingering odor in the home. If your dog has this problem, you may elect to remove the anal sacs.