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Not all dogs need their anal glands expressed, only some dogs do and often these are dogs who are particularly predisposed either due to conformation or from being overweight, but why do dogs have anal glands in the first place and what causes them to need to be expressed? 

Veterinarian Dr. Ivana Crnec clarifies the role anal glands in dogs play and provides insights on things that can go wrong.

Under the Hood

If you raise your dog’s tail to the flagpole position, the anal sacs are located under the skin at the "four and eight o’clock" positions around the rectum.

 The anal sacs contain a cocktail of smelly, fatty acids, each of which has a specific role in communication between dogs. This smelly cocktail is secreted in the anal glands and then collected in the anal sacs

The anal sacs are part of the dog’s apparatus for marking territory. Each time a dog passes stools, muscles around the anus squeeze some of the fluid out which anoints the feces with a few drops of a substance produced within the sacs. Other dogs come along and sniff this material, thus being informed of who passed the stool. 

Interestingly, the secretion is individual for every dog – something like a scent signature. Its role is to alert other animals and repel enemies. Sniffing the anal sac secretion is like reading the daily canine paper – it keeps dogs well-informed. 

Problems With the Anal Sacs

Estimates about the incidence of anal sac problems in dogs vary. While veterinary schools report an incidence of 12 percent in the general dog population, vets in general practice see a much higher incidence.

 The most common sign that indicates anal sac issues is increased licking or scooting. Some affected dogs simply jump up from a resting position as if they have been startled or felt a sudden pain. Other symptoms include the dog biting its rear end, constipation, difficulties while passing stools, bad smell, itching, snapping and growling if you try to touch the dog's tail and anus.

Dachshunds, Retrievers and Spaniels are particularly prone to anal sac problems. The risk of anal sac problems is particularly high in small dogs suffering from obesity. 

Generally speaking, dogs that tend to pass softer stools (due to dietary indiscretions or medical issues) are more likely to develop anal sac issues. This is because the softer the stool, the less power it has to naturally express the sacs. It is also postulated that anal sac conditions are more common among dogs that are not on regular exercise regimens.

Below are found several anal sac problems observed in dogs. 

Anal gland secretions in dogs are individual, no wonder why dogs are so attracted to sniffing under tails!

Anal gland secretions in dogs are individual, no wonder why dogs are so attracted to sniffing under tails!

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Blocked Anal Glands 

As mentioned, anal glands are most likely to become blocked if the stools are soft because the contents will not be squeezed out.

Uncomplicated blocked anal sacs are diagnosed by squeezing the sacs to feel if they are full. They can be emptied by either external or internal pressure (see below for instructions). Some dogs need to have their anal sacs emptied frequently – as often as every month. You can do this at home if you are willing and if your dog allows it.

Anal Sac Infection 

Anal sac infection (anal sacculitis) causes a painful swelling on the affected side, to the left or right of the anus. Usually only one side is affected.

Gently squeezing the anal sac produces repellent, purulent (pus-filled) material that is yellow, green or blood-tinged. A bacterial culture and an antibiotic sensitivity test are usually undertaken.

Infection is treated by flushing the sac with an appropriate antiseptic or antibiotic while the dog is deeply sedated or anesthetized. Infected anal sacs sometimes warrant a course of oral antibiotics. The most commonly used antibiotic for this purpose is clindamycin.

 Most dogs with infected anal sacs need pain medication for several days or at least until the swelling and inflammations subside. The pain medication of choice is the non-steroid anti-inflammatory drug – meloxicam.

Anal Sac Abscess 

If the anal sac canal (leading from the sac to the mucosal lining just inside the anus) is blocked, the sac may swell and burst through the skin on either side of the anus, producing a draining abscess. 

The painful swelling is initially red but just before rupturing it turns purple. The abscess rupture reduces the pain significantly.

If an abscess has not already ruptured it is treated by being lanced (cut open) often under general anesthesia. The abscess and sac are flushed with a solution containing an antiseptic and antibiotic. Oral antibiotics and pain control medications are also given.

 In rare circumstances, if the anal sacs are prone to frequent issues, surgical removal is recommended. The anal sacs participate in the dog’s territory marking activity. In domestic dogs this is an unnecessary behavior. Therefore, surgical removal of the anal sacs does not have adverse effects on your dog. However, the removal procedure (called sacculectomy) is delicate and complicated and not all veterinarians perform it. 

Now That You Know...

As seen dog anal glands are prone to being blocked and in some cases, may need to be expressed. Knowing how to express the glands and how to prevent anal gland issues in the first place is important. 

  • Only empty the anal sacs if they need emptying. Ask your vet for guidance. 
  • Learn how to express the glands. Have your vet show you first. First, put on disposable latex gloves. Raise your dog’s tail to a flagpole position, which causes the anus, and the anal sacs, to protrude. Next, place your fingers on either side of the anus, at the "four and eight o’clock"  positions. You will feel two lumps like grapes if the anal sacs are full. 
  • Gently but firmly squeeze each sac with your thumb and forefinger, milking upward and outward. Your fingers will be at the "three and nine o’clock" when they complete the squeezing action. The anal secretions will be discharged on to your glove and may drip on to the floor. Wipe the secretions from the anus with cotton, and then clean the area with a damp tissue. 
  • Always give your dog a treat immediately after expressing your dog's glands to reward him for allowing you to do something so intimidating.
  • Sometimes your dog’s anatomy can prevent external emptying. In such cases, it is advisable to visit your vet, who will empty them by using internal pressure. You should always contact your vet if the anal sacs are blocked or if the substance secreted is overwhelmingly smelly, yellow, green or blood-tinged. 
  • Maintain your dog on a healthy body weight. 
  • Practice a regular exercise regimen.
  • Promote healthy stool formation (by adding more fiber in your dog’s diet)
  • Supplement with fish oil (which has anti-inflammatory properties).

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