Anal gland impaction

They're not the stuff of dinner party conversations, but knowing how to spot a problem could save your dog a lot of misery.

Sound familiar?

Picture the scene. You've just washed your dog from top to tail using the finest shampoo and conditioner money can buy, but even after drying him, the same horrible fishy odour you noticed pre-groom is still lingering in your poor nostrils. 'So where's the smell coming from?' you wonder. It's highly likely that your dog's smelly anal glands are the culprits.

What are anal glands?

Anal glands (or anal sacs) are relatively small glands found on either side of your dog's anus (and no, humans don't have them!). They're found just below the surface of the skin between the external and internal sphincter muscles.

Why do dogs have anal glands?

Dogs usually use these glands to identify each other and mark territory by making a distinctive thick, foul smelling, oily liquid. This is the reason dogs smell other dogs' bottoms when they meet and greet, standing tense with tails erect to swap their own unique smells (a bit like individual fingerprints).

How do dogs empty their anal glands?

Unlike the skunk, domestic dogs and cats have largely lost their ability to empty their anal glands voluntarily. Your dog's anal glands may empty when walking around, especially when they're stressed, creating a very sudden unpleasant change in smell. Going for a poo puts natural pressure on the rectum walls to empty their glands which can lubricate the anal opening, making it easier for them to go.

How can anal glands become impacted?

Anal glands can fill for a number of reasons; most commonly when there hasn't been enough pressure to empty the glands, such as, after a few days of diarrhoea. Whenever they haven't emptied properly, there's a chance that glands can become blocked, impacted and swollen. If they're impacted for too long they can build up nasty bacteria, causing pain, increased swelling and sometimes even abscesses and fever.

How do I know if my dog may have a problem?

Signs of anal sac impaction can include:

Which breeds are affected by anal sac impaction?

All types of dogs can develop anal sac impaction and it’s estimated that each year around 4% of dogs are affected by it. The risk of developing anal sac impaction is higher in older dogs. Research has found that some breeds and types appear to be more at risk of developing this condition than others, including: Cavalier King Charles Spaniels, King Charles Spaniels, Crosses between Cocker Spaniels and Poodles, Shih-tzus, the Bichon Frise and Cocker Spaniels.

How are impacted anal glands treated?

Vets will usually treat this by expression of the gland (usually far too painful in the conscious patient), antibiotics and pain relief, and even repeated flushes of the glands. 

With rare cases of recurrent infection or presence of a specific type of malignant tumour, anal glands may be removed surgically. The potential complications of this specialist type of surgery, however, make the operation strictly reserved for essential cases only.

Should I regularly empty my dog's anal glands to prevent this happening?

Not all dog experts agree the anal glands should be interfered with in any way - unless the dog is showing signs of a problem. Applying pressure to an anal sac impaction or infection could cause the gland to rupture, and lead to bleeding and painful complications for your dog. Always speak to your vet for advice.

Article author

This article was written by Marc Abraham, a vet based in Brighton who regularly appears on UK television.