What Are Anal Glands in Dogs?
Anal glands, also called anal sacs, are two small pouches located just inside your dog's anus, positioned roughly at the four o'clock and eight o'clock positions. Each sac is connected to the skin surface by a tiny duct. They produce a thick, oily secretion with a distinctive and pungent smell that is unique to each individual dog.
In the wild, this secretion serves as a chemical identity card. Dogs use it for scent marking and communication with other animals. When a healthy dog defecates, the pressure of passing a firm stool naturally squeezes the glands and releases a small amount of the fluid. This natural expression is how the glands are meant to empty themselves.
Problems arise when this process does not happen efficiently, which is surprisingly common in domestic dogs.
Which Breeds Are Most Commonly Affected?
Any dog can develop anal gland problems, but smaller breeds tend to be affected far more frequently than larger ones. The reasons are not entirely clear, but it is thought that the anatomy and muscle tone around the anal area in small dogs may be less effective at natural expression.
Breeds that appear at the vet most often for anal gland issues include the Chihuahua, Cocker Spaniel, Miniature and Toy Poodle, and the Bichon Frise. Overweight dogs of any breed are also at higher risk, as excess body fat around the hindquarters can interfere with normal gland function.
The Three Main Anal Gland Problems
Impaction
Impaction is the most common anal gland problem seen in dogs. It occurs when the secretion inside the sac becomes too thick to drain through the duct normally. The material builds up and hardens, causing the sac to become swollen and uncomfortable. If left untreated, impaction can progress to infection.
Infection and Sacculitis
Bacteria can colonise an impacted or otherwise compromised anal sac, leading to infection, a condition known as sacculitis. The gland becomes inflamed, painful and filled with pus as well as the normal secretion. Dogs with sacculitis are often visibly uncomfortable and may be reluctant to allow anyone near their rear end.
Abscess
An abscess forms when an infection within the anal sac progresses and the surrounding tissue becomes severely inflamed. The skin around the anus may rupture, releasing a foul-smelling discharge that can be bloody or contain pus. An abscess is a veterinary emergency and requires prompt treatment to prevent the infection from spreading and to allow the tissue to heal properly.
Signs That Your Dog Has Anal Gland Problems
Recognising the signs early can prevent a minor issue from becoming a painful and complicated problem. Common signs include:
- Scooting along the floor, dragging the rear end on carpet or grass
- Biting, licking or chewing at the base of the tail or around the anus
- A persistent fishy or unpleasant smell, particularly noticeable when the dog sits near you
- Swelling, redness or visible lumps near the anus
- Reluctance to sit down or shifting position frequently when seated
- Pain or straining when defecating
- Brownish staining on the fur around the rear end
- The dog appearing distressed or anxious without an obvious cause
Scooting is often mistakenly attributed solely to worms, but anal gland discomfort is a far more frequent cause in adult dogs.
How Anal Glands Are Expressed
When glands fail to empty on their own, manual expression is required to relieve the build-up. This can be performed using two different techniques.
External Expression
External expression involves applying gentle pressure to the outside of the gland through the skin. It is the technique most commonly used by groomers and is suitable for straightforward cases of mild impaction. The glands are located by feel and squeezed gently towards the duct opening.
Internal Expression
Internal expression is performed by a veterinary professional who inserts a gloved finger into the rectum to compress each gland individually from inside and outside simultaneously. This technique is more thorough and is preferred when the glands are particularly full, impacted or when infection is suspected. It allows the vet to assess the contents and consistency of the gland and check for any abnormalities.
Many owners are keen to express their dog's glands at home to save on veterinary costs. Whilst external expression can be learned, it is advisable to have a vet demonstrate the technique first and to leave internal expression to professionals. Incorrect technique can cause injury or push infection deeper into the tissue.
The Role of Diet and Fibre
Diet plays an important role in anal gland health. When a dog passes a firm, well-formed stool, the physical pressure against the glands during defecation helps to empty them naturally. Loose or soft stools do not provide sufficient pressure to achieve this.
Feeding a high-fibre diet can significantly reduce the frequency of anal gland problems in susceptible dogs. Adding fibre to the diet makes stools bulkier and firmer. Good sources of fibre for dogs include plain cooked pumpkin, green beans or a vet-recommended fibre supplement. Some veterinary diets are specifically formulated to support anal gland health. Always discuss dietary changes with your vet before making significant adjustments, particularly if your dog has other health conditions.
When to See a Vet
Routine anal gland expression by a groomer or vet is suitable for dogs that need regular maintenance. However, certain signs indicate that a more urgent veterinary assessment is needed:
- Visible swelling, heat or redness around the anus
- Any discharge containing pus or blood from the anal area
- Signs of significant pain, such as crying out when sitting or being touched near the tail
- A ruptured abscess or open wound near the anus
- Recurring infections despite regular expression
In these cases, your vet may prescribe antibiotics, anti-inflammatory medication or pain relief, and will advise on further management.
Anal Sacculectomy: When Surgery Is Considered
For dogs that suffer from recurrent infections or chronic anal gland problems that do not respond to medical management, surgical removal of the anal sacs, known as anal sacculectomy, may be recommended. This procedure removes the problem permanently, though it carries a small risk of complications such as faecal incontinence and should only be considered after conservative treatments have been exhausted.
Surgery may also be necessary if a tumour is discovered within or around the anal sac. Anal sac adenocarcinoma is a serious malignant tumour that can occur in this region. It may not always cause obvious external signs in its early stages, which is one reason why any unusual swelling near the anus should be assessed by a vet promptly rather than assumed to be a straightforward gland problem. Early detection significantly improves outcomes.
Summary
Anal gland problems are uncomfortable for your dog but are generally manageable when caught early. Regular monitoring, an appropriate diet and prompt veterinary attention when signs of infection appear will keep most dogs comfortable. Small breeds in particular benefit from routine checks during grooming appointments. If your dog is scooting, smelling fishy or showing any of the signs described above, a visit to your vet is always the right first step.