Small dog breeds are the most likely to need their anal glands expressed, with Chihuahuas topping the list as the most commonly affected breed in at least one veterinary study. But size isn’t the only factor. Roughly 1 in 6 dogs will deal with anal sac disease at some point, and certain body types, weights, and even tail shapes can raise the risk regardless of breed.
Why Some Dogs Can’t Empty Their Glands Naturally
Every dog has two small scent glands located just inside the anus, one on each side. These glands produce a pungent, oily fluid that gets stored in tiny sacs between the muscles that control bowel movements. When a dog passes a firm stool, the pressure naturally squeezes those sacs and pushes the fluid out onto the surface of the stool. This is the scent other dogs are investigating during that familiar greeting sniff.
The system works well when stools are consistently firm and bulky enough to create that pressure. Problems start when the stools are too soft, the muscles around the anus are weak, or the duct openings that allow the fluid to escape become clogged. When the sacs don’t empty on their own, the fluid thickens and builds up, creating what veterinarians call impaction. Left untreated, impaction can progress to infection and eventually a painful abscess that may rupture through the skin near the anus.
Small Breeds at Highest Risk
Small and toy breeds are disproportionately affected by anal sac problems. Their smaller anatomy means the ducts are narrower and more easily blocked, and their stools may not generate enough pressure to fully empty the glands. Cornell University’s veterinary college notes that smaller dogs are affected more often than larger breeds, with Chihuahuas identified as the most commonly affected small breed. The Merck Veterinary Manual similarly states that small breeds are predisposed while large and giant breeds are rarely affected.
Beyond Chihuahuas, the breeds most frequently seen by veterinarians for anal gland issues include Toy and Miniature Poodles, Cocker Spaniels, Beagles, Basset Hounds, Dachshunds, Shih Tzus, Lhasa Apsos, and Bichon Frises. These breeds share traits that contribute to the problem: compact body frames, a tendency toward soft stools, and in some cases a genetic predisposition to produce thicker anal gland secretions that don’t flow as easily.
The German Shepherd Exception
One large breed stands out. German Shepherds account for 84% of cases of a related condition called anal furunculosis, a chronic, painful inflammation of the skin surrounding the anus that involves the anal sacs. Researchers initially suspected this was linked to the breed’s thick, low-carried tail creating a warm, moist environment over the anal area, combined with an unusually high number of sweat glands in the surrounding skin. That theory has been debated, since other breeds carry their tails similarly without developing the condition, suggesting a genetic or immune component specific to German Shepherds.
While anal furunculosis is different from the simple impaction that small breeds experience, German Shepherd owners should watch for the same warning signs and may need to pay closer attention to anal gland health than owners of other large breeds.
Weight, Diet, and Other Risk Factors
Breed alone doesn’t determine whether your dog will need help. Overweight dogs of any breed tend to have chronic anal sac problems because excess body fat interferes with the muscles’ ability to squeeze the sacs during defecation. Poor muscle tone, which can come with age or inactivity, has a similar effect.
Diet plays a significant role. Dogs that eat low-fiber diets or have frequent soft stools lose the natural pressure that empties the glands. Adding fiber to your dog’s diet, either through a higher-fiber food or a supplement your vet recommends, can bulk up stools enough to restore natural expression during bowel movements. This is one of the simplest preventive steps you can take, especially for breeds already at higher risk.
There’s also an ironic twist: frequent manual expression itself may cause problems. Veterinary sources note that repeated squeezing of the glands can damage the delicate ducts, potentially making a dog more dependent on manual expression over time. This is why most veterinarians advise against routine expression in dogs that aren’t showing symptoms.
Signs Your Dog Needs Gland Expression
The classic sign is scooting, when your dog drags its rear end across the floor or ground. Dogs do this because their anal glands are uncomfortable, and the pressure or friction provides temporary relief. Other signs include excessive licking or biting at the area around the tail, a fishy or unusually foul smell, swelling or redness near the anus, and visible discomfort when sitting. Dogs with more advanced impaction or infection may cry out in pain and hold their tail down against the body.
If you notice a swollen, discolored area near one side of the anus, that may indicate an abscess forming, which needs veterinary attention promptly before it ruptures.
Professional Expression vs. Doing It at Home
There are two techniques for manually emptying anal glands: external and internal. External expression involves applying pressure on the outside of the glands through the skin. It’s the method most commonly attempted at home or performed by groomers, but it often doesn’t fully empty the sacs, especially when the fluid has thickened.
Internal expression, where a gloved finger is inserted into the rectum to squeeze each sac individually from the inside, is more thorough and is the method veterinarians use. It allows them to feel the consistency of the fluid and check for abnormalities like thickening, blood, or unusual texture that could signal infection or, rarely, a tumor. If your dog needs regular expression, having it done at a veterinary clinic at least some of the time gives your vet a chance to monitor for these changes.
How Often Expression Is Needed
There’s no universal schedule. Some predisposed dogs need expression every 3 to 4 weeks, while others manage fine with occasional help a few times a year. The key is to watch for symptoms rather than expressing on a fixed calendar. If your dog goes months without scooting or showing discomfort, the glands are likely emptying on their own, and intervening could do more harm than good.
For dogs with chronic, recurring impaction that doesn’t respond to dietary changes or weight management, veterinarians may discuss surgical removal of the anal sacs. This is a permanent solution, but it carries a small risk of complications, so it’s typically reserved for severe cases. Most dogs with anal gland issues can be managed comfortably with a combination of dietary fiber, weight control, and expression only when symptoms appear.