Anal Sac Disease in Dogs

Scooting? Licking Under the Tail? Skunky Odor?

At the Animal Hospital at Thorndale, we have seen and smelled it all! When dogs try to empty their inflamed or impacted anal glands, or when we do it for them, you do not want to be in a closed space with them. Pee-yew!

The anal sacs (or glands) are located on either side of the anus at the 8:00 and 4:00 o’clock positions just under the skin. They connect to the anus by means of small canals, or ducts. Anal sacs produce and store a dark, foul-smelling fluid. These are the same types of organs that a skunk sprays to scare away its enemies. Although dogs can use these for the same purpose, most dogs live in an environment where there are no enemies. If the glands are not emptied sufficiently with defecation, the fluid builds up, solidifies, and becomes an ideal environment in which bacteria can grow. Dogs with atopic allergies or food allergies often have issues with anal sac disease because they develop skin inflammation that prohibits normal emptying of the sacs during defecation. Some breeds such as Cocker Spaniels overproduce the anal sac material.

Prevalence

The prevalence is higher in smaller breeds of dogs but any dog can have a problem.

Causes

There are 4 diseases that occur in the anal sacs in dogs.

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 glands, the skin over the anal sac breaks open, and the pus drains onto the skin.
4. Anal gland carcinoma (or cancer)

Symptoms of anal sac disease are:

• Scooting or dragging the anal area
• Excessive licking under the tail
• Pain, sometimes severe, near the tail or anus
• A swollen area on either side of the anus
• Bloody or sticky drainage on either side of the anus

Diagnosis

Physical examination, including a rectal examination, will usually confirm the diagnosis. Certain blood tests (especially a blood calcium level) may be indicated if cancer is suspected.

Treatment

The treatment for impaction is to express the anal sacs and clean out the solidified material. For infection, the glands must be expressed and antibiotics administered to kill the bacteria. If the infected anal gland in the dog develops an abscess, the abscess may need to be surgically drained and antibiotics administered. Repeated abscessation may require surgical removal of the glands. The treatment for cancer is based on further diagnostics and may involve surgical removal of the affected gland followed by appropriate therapy.

Rarely, 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 wherever they have been. This is another indication for anal gland removal. There does not appear to be any other way to stop this, and these dogs usually do not outgrow this problem.

Prognosis

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