Gazette Vet: The Rear Issue


This month we’re going to get familiar with one of my least favorite parts of my job—anal glands! Warning: anal glands are disgusting things to talk about, so if you’re easily grossed out, go read Roscoe’s weather column. I won’t be offended, and I promise to write about puppies and kittens or something nice next month.  

This is an important topic, however, because anal glands are a very common problem in dogs and an occasional problem in cats as well. So, what are they? What can possibly go wrong with them? Let’s take a journey to the back woods together!

Anal glands (also referred to as the anal sacs) are simply scent glands that both dogs and cats have. There are two anal sacs, one on each side of the anus at approximately the 4 and 8 o’ clock positions. They are each typically about 1-2 cm in diameter and they are located just under the skin with a small duct that empties right at the anal opening.

The purpose of the anal glands is scent communication. Inside of each of these glands is a very foul-smelling, oily liquid that dogs and cats can express when they have a bowel movement or even voluntarily when scared or excited. Since dogs and cats have such incredible senses of smell, it would make sense that they have some special glands to communicate their whereabouts better.  Also, when dogs smell each other’s rears–anal glands. “Oh, you’re the dog whose owner never picks up your poop over on that corner!”

Unfortunately, in our domesticated pets, the anal glands are ripe with problems that cause scooting, licking, smells, and infections. You can see why anal gland problems are one of my favorite things to deal with…NOT!


Impaction is by far the most common anal gland problem and leads to the most common clinical sign associated with the anal glands–scooting. Anal gland impaction happens when the normally thinner liquid in the anal glands starts to thicken or become “chunky.”  The thicker material has trouble getting squeezed out of the tiny anal sac duct opening, which is only about 2mm wide.  Meanwhile, the glandular material lining the anal sacs continues to produce material, and so the anal glands get “full.”  We don’t really know if this causes pain, itching, or another type of discomfort, but generally when anal glands are becoming full, you will see your dog start to scoot its rear along the floor. While it’s really not a big deal to occasionally see your dog scoot, these dogs are scooting daily and sometimes licking their rears as well.  

Generally, they will come to us for this problem and we will put some gloves on and manually empty them out.  Not many dogs appreciate this and there are zero cats in this entire universe who appreciate this. However, by manually emptying them out, we can relieve the pressure and stop the scooting.  

Why do some dogs and cats get anal sac impaction? We really don’t know. Small dogs are extremely overrepresented, making up about 85 percent of the cases we see, so conformation surely has something to do with it. Maybe they are unable to effectively empty them out on a regular basis.  Perhaps diet has something to do with it as well, but this is unproven, and I’ve never had an anal gland impaction case resolve by adding more fiber into the diet.  

There are two ways of trying to express the anal glands. Many pet owners and groomers will try to “externally” empty them – taking a baby wipe and covering the anus and then pushing inward to try and empty the glands. This is rarely very successful or thorough, but may work okay for some dogs.  The best way to express anal glands is by putting on gloves and expressing them “internally”.  This is a two-person job and takes some practice and most people choose to leave this to a professional. It is not a fun job!

For many dogs and cats, emptying the anal glands provides some reasonable control. We may only need to express them a few times a year, which seems like a win. Some dogs, however, seem to start scooting again quite soon after and perhaps have one of the problems below.


Anal sacculitis is a term we use to describe inflamed or infected anal glands and although scooting is often a clinical sign here, licking and discharge are more common. With anal sacculitis, the glands become either really itchy or painful and will often leak some pretty foul-smelling discharge around the rear. When we express these glands, we often get either blood or pus, which pretty clearly indicates a problem. Treatment varies, from antibiotics, to steroids, to flushing out the glands and infusing medication into them.  

“Inappropriate expression”

This is not so much a medical problem as it is a big nuisance for the owners. These dogs (I don’t really see this in cats) just seem to randomly express anal gland material on the couch, in the car, on their owner’s beds. Yuck! Perhaps these dogs have too much muscle tone and accidentally express them when they get a little scared or excited, or maybe the ducts are just a bit leaky. Either way, this is probably one of the hardest problems to fix, because there’s not really a fix except to surgically remove them. 

Abscess and rupture

These typically come out of the blue. These dogs and cats for some reason don’t usually have a history of any scooting and then one day there is a large painful swelling or draining wound next to their anus. Somehow, the anal gland has ruptured under the skin, releasing all if its normal contents, including millions of fecal bacteria, into the subcutaneous space. This quickly causes a lot of pain and infection and in just a day or two will actually form an abscess that then ruptures through the skin. In almost all of these cases, the pets have very thick, paste-like anal gland material and they likely ruptured because they were unable to naturally be expressed. I can’t explain why they never seem to scoot.  

These pets need antibiotics to get the infection under control and then later when they’re not so painful we try to fully empty out the rest of the anal gland material. Some anal glands never heal normally and need to be removed, whereas others seem to scar up and not cause problems again.


Unfortunately, this last category is not uncommon. Almost all masses of the anal glands are cancerous anal gland adenocarcinomas. These typically occur in older dogs and the dog may present with scooting or bloody discharge. When we try to express them, we feel can simply feel the mass and then we know we need to quickly remove the anal sac. I have had many dogs that I’ve cured by promptly taking them to surgery. However I’ve also had many dogs who have died months or even years later as a result of the cancer spreading to other parts of the body. 

If you’ve made it through this column, consider yourself one tough person! Perhaps you’ve missed your true calling in life? Or maybe not. But don’t worry, we’ve got your pet’s rear covered.  


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