This article is not for the squeamish! It’s a topic that many pet parents wish they could avoid, but the reality is that understanding the function of your dog’s anal sacs and the potential complications is important.
The anal sacs -- also known as anal glands -- are two small repositories located around your dog’s anus that continually produce a foul-smelling substance. The odor of that substance is what identifies your dog and marks their stool as a way to establish territory. This is why rather than shaking paws when two dogs meet, they smell each other’s rear ends.
Here we will review what you need to know about your dog’s anal sacs and anal sac disease.
How Do Anal Sacs Work?
If looking at your dog’s anus straight on, the anal sacs are located between the internal and external anal sphincter muscles at 4 o’clock and 8 o’clock. The sacs are lined with sebaceous glands (oil glands) and apocrine glands (sweat glands) that produce a somewhat oily, brownish in color, and awful smelling substance. The sacs are connected to the outside by small ducts that open just inside of the anus.
The anal sacs are often emptied by the pressure caused by a large, firm stool. They can also empty if a dog is afraid or upset and responds with forceful sphincter contractions.
In some dogs, the glands do not empty regularly as they should, which can lead to a blocked accumulation of secretions known as impaction.
Anal Sac Impaction: Causes, Symptoms, and Treatment
Anal sac impaction occurs when the sacs do not empty and secretions accumulate. This can happen if a dog is passing soft or small stools that do not create enough pressure to empty the sacs. It can also occur as a result of anal sphincter muscle dysfunction or if the openings of the anal sacs are blocked by thick, semi-solid secretions (which, for unknown reasons, some dogs are prone to producing).
If your dog’s anal sacs are impacted, they will be distended and tender. In addition, your dog may “scoot,” chase their tail, and lick or bite their rear end. Impactions are most common in small-breed dogs and overweight dogs, and if left untreated can lead to infection, abscess, and ultimately rupture. This whole cycle is what is referred to as anal sac disease.
Anal sac impaction is treated by manually expressing -- or emptying -- the anal glands. Your veterinarian can do this or can show you how to do it at home. If your dog has recurrent impactions, it is a good idea to learn how to do it and manually empty the sacs on a schedule set by your veterinarian. Your veterinarian may also prescribe a high-fiber diet to increase the size and firmness of your dog’s stools.
How to Express Your Dog’s Anal Sacs
Sounds pleasant, doesn’t it? Once you get used to it, emptying your dog’s anal sacs becomes just as routine as brushing their teeth or trimming their nails.
We’ll provide some instruction here, but you should consult your veterinarian before attempting to express your dog’s anal sacs for the first time.
1. Put on latex or plastic surgical gloves. (Trust us: you don’t want to get this substance on your hands!)
2. Raise your dog’s tail and locate the openings at 4 o’clock and 8 o’clock.
3. If the anal sacs are full, they will feel like small, hard lumps.
4. Take the skin surrounding the sacs between your thumb and forefinger and squeeze. If the anal sac is impacted, you may need to put your forefinger inside of the anal canal and have the thumb on the outside.
5. The secreted substance will smell very strong, and should be liquid and brownish in color. If the substance is pus-like, yellow, or bloody, the anal sacs may be infected, and you should contact your veterinarian.
6. To clean up, wipe your dog’s rear end with a damp cloth or spray with a hose.
Anal Sac Infection: Symptoms and Treatment
Anal sac infection is a potential complication of anal sac impaction. The symptoms of an anal sac infection include painful swelling of the anus, pus-like, yellow, or bloody discharge, discomfort when defecating, and “scooting,” licking, or biting the rear end.
An anal sac infection will be treated by your veterinarian. They will manually empty the sacs and place an antibiotic directly into the sac. They may also prescribe your dog with an oral antibiotic. Dogs with recurrent anal sac infections sometimes have their anal sacs surgically removed.
Anal Sac Abscess: Symptoms and Treatment
Anal sac abscesses can occur when there is a severe anal sac infection. If your dog has an anal sac abscess, they will show the same symptoms of anal sac infection and may also have a fever. An abscess will begin as red and eventually turn purplish, and may ultimately rupture through the skin. The substance that comes out will likely be greenish yellow or bloody.
If you suspect that your dog has an abscess, you should contact your veterinarian right away. If the abscess has not already ruptured, your veterinarian will be able to lance it, clean it, and then place your dog on an oral antibiotic. If the abscess has already ruptured, treatment is more intensive and may include surgery to clean the sacs, removed affect tissues, and place a drain to ensure that fluids drain normally.
In these cases, your veterinarian may also suggest removing the anal sacs at a later date.
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