If your dog has started scooting across the carpet, licking under their tail or leaving a fishy smell on the couch, their anal glands are a likely suspect. This guide is for dog owners who want to know what these glands are, what goes wrong with them, and whether they need emptying at the vet or the groomer.
The short answer: in most dogs the glands empty on their own, and a dog that has never had a problem does not need them emptied. If your dog shows signs of trouble, see your vet first. A painful swelling, blood or pus beside the anus needs a vet as soon as possible.
What are anal glands and what do they do?
Anal glands, also called anal sacs, are two small pouches on either side of the anus, at roughly the four o’clock and eight o’clock positions. They hold a strong-smelling fluid that gives your dog’s stool its own scent and works as a kind of territorial “calling card” for other dogs.
The fluid is normally squeezed out by muscle contractions each time your dog passes a stool. Dogs can also release it when they are frightened, nervous or excited, which is why a scared dog sometimes leaves a sudden fishy smell behind.
What are the signs of an anal gland problem?
The best-known sign is scooting, where your dog drags their bottom along the ground. Other signs include:
- licking or biting at the bottom or the base of the tail
- a strong fishy smell, or fluid left on bedding or furniture where your dog sits
- straining, or pain when passing a stool
- holding the tail down, sitting down suddenly or turning to look at the back end
- signs of pain, such as growling or snapping, when the tail or bottom is touched
- redness, swelling or a bloody discharge near the anus
Most problems are simple blockages. A Royal Veterinary College study of 104,212 dogs at 110 UK practices found that 4.4% had an anal sac disorder diagnosed during 2013. Of those cases, 78.6% were impactions, 12.2% were inflammation or infection of the sac (sacculitis) and 8.9% were abscesses.
What causes anal gland problems?
A gland becomes blocked, or impacted, when it does not empty properly and the fluid thickens into a pasty, brown material. Bacteria can then get in and cause infection, and an infected sac can fill with pus and form an abscess.
Factors that vets link to problems include:
- soft stools or chronic diarrhoea, which may not press on the glands hard enough to empty them
- constipation
- a low-fibre diet
- skin allergies, including food allergy and atopic dermatitis
- narrow gland openings or other differences in the shape of the sacs
Size and breed matter too. Small breeds are affected more often than large and giant breeds, and the problem is usually seen in dogs over a year old. In the RVC study, Cavalier King Charles Spaniels, King Charles Spaniels, Cockapoos, Shih-tzus, Bichon Frises and Cocker Spaniels had higher odds than crossbreeds, and flat-faced (brachycephalic) dogs had 2.6 times the odds of long-nosed types. Labradors, Border Collies, Staffordshire Bull Terriers, Lurchers, German Shepherd Dogs and Boxers had lower odds.
Weight is less clear. VCA says overweight dogs tend to have ongoing problems because their glands do not empty well, and PDSA puts it down to weak muscles around the anus, but the RVC study found no evidence linking obesity to anal sac disorders, and The Kennel Club notes that vets disagree on this point. Keeping your dog at a healthy weight is still good for their overall health. Ask your vet whether more fibre in the diet would help, since it bulks up the stool and helps the glands empty.
Does every dog need its anal glands expressed?
No. PDSA says that if your dog has never shown signs of an anal gland problem, there is no need to have the glands examined or emptied. It adds that emptying them at a grooming parlour is not needed unless your vet has advised it, and that emptying could cause problems if it is done the wrong way or too often. The Kennel Club also warns that expressing the glands too often, especially when it is not necessary, can cause further harm.
Some dogs do have repeated trouble. For them, a vet may recommend checking and emptying the glands on a regular schedule. One study of 20 dogs with anal sac disease, cited in the RVC paper, needed repeated emptying every two months.
How is expression at a groomer different from a vet visit?
At the vet, the glands are checked during a rectal examination, where the vet can feel each sac and empty it at the same time. If the glands cannot be emptied this way, the vet may flush them under sedation or general anaesthesia. Because the vet can tell a simple blockage from an infection or abscess, they can also prescribe treatment such as pain relief or antibiotics when it is needed.
A vet can also check for tumours. Older dogs can develop a cancer of the anal sac called adenocarcinoma, and the MSD Veterinary Manual says a tumour should be suspected when a sac feels firm and enlarged and cannot be emptied. These tumours are usually not painful, and affected dogs may drink and urinate more than usual (from high blood calcium) or strain to pass a stool.
A groomer is not a vet, and cannot diagnose an infection, check for a tumour or prescribe treatment. That is why The Kennel Club advises talking to your vet first, even though some groomers offer the service.
When should you see a vet urgently?
Contact your vet as soon as possible if you notice:
- a red or swollen area beside the anus
- a wound near the bottom, or discharge, blood or matted fur around it
- greenish-yellow or bloody pus coming from an opening beside the anus, which can mean an abscess has burst
- your dog straining or in pain when passing a stool, or eating less and seeming low in energy
- an older dog with a firm swelling near the bottom, or one who is drinking and urinating more than usual
Do not try to treat a suspected abscess at home, because PDSA warns that you could cause serious damage and pain. VCA warns that an untreated anal sac infection can quickly spread and cause severe damage to the area. For milder signs such as occasional scooting, book a normal vet appointment rather than waiting for it to pass.
How Mutt Cuts can help
Anal Gland Cleansing is one of our Extra Spoils for dogs, and you can find our dog grooming options on our services page. In line with PDSA and Kennel Club advice, it makes sense to add it only if your vet has recommended regular emptying for your dog. If your dog has never had a problem, there is no need for it. If your dog is scooting, sore or has a swelling, please see your vet before booking a groom. If you have questions about adding it, you can reach us through our contact page.