Anal Sac Disease

anatomy of anal area showing sacsWhat are the anal sacs?

Popularly called ‘anal glands’, they are two small pouches situated on either side of the anus at approximately the 4 o’clock and 8 o’clock positions. The sacs are lined with numerous specialised sebaceous (skin) glands that produce a foul smelling secretion. Each sac is connected to the outside by a small duct which opens just inside the anus.  

What is their function?

The ‘glands’ are present in both male and female dogs and are normally emptied when the dog defaecates. The secretion acts as a territorial marker. This is why dogs are so interested in one another’s faeces.

Why are they a problem?

Anal gland (sac) disease is very common in dogs. The sacs frequently become impacted, probably due to blocking of the ducts. This is followed by thickening and hardening of the secretion. It is then painful for your dog to pass motions. The secreted material within the anal sacs (glands) forms an ideal medium on which germs can multiply so that an abscess can easily form. Pain increases and sometimes a red angry looking swelling will appear on one or both sides of the anus indicating abscessation. These abscesses often burst and release a quantity of greenish yellow or blood stained pus.

How will I know if my dog has anal sac problems?

The first sign is often ‘scooting’ or dragging the behind along the ground. There may be excessive licking or biting, often at the root of the tail rather than the anal area. Anal sac problems are very painful. A normally placid dog will often become uncharacteristically aggressive if you attempt to groom around the root of the tail.  Sometimes you will see a swelling as indicated above, or even pus draining from a burst abscess. 

"The first sign is often ‘scooting’ or dragging the behind along the ground. There may be excessive licking or biting, often at the root of the tail rather than the anal area."

What should I do?

Problems with the anal gland are common in all dogs, irrespective of size or type.  If you are at all concerned do not hesitate to call us. Treatment for impaction involves removing the solidified material.  If in pain, this may require a sedative or even an anaesthetic. If the glands are infected antibiotics have to be prescribed and sometimes instilled into the glands. If there is an abscess surgical draining may be necessary therefore the sooner we see the patient the better.

Is the condition likely to recur?

Many dogs have recurrent anal sac impaction due to blocking of the secretions in the ducts or the sacs themselves. If this recurs frequently, surgical removal of the sacs is indicated since repeated treatment often results in scarring and narrowing of the duct.

Are anal glands unnecessary for my dog? Will removal have any adverse effects? 

As explained anal glands produce, to us, a pungent smelling secretion which allows the dog to accurately define territory. With domestication this is largely unnecessary and thus surgical removal will not in any way disadvantage your dog.

dog under general anaestheticAre there any other risks attached to surgery?

It is specialised surgery but is commonly undertaken by vets in practice since the problems are so common. Modern anaesthetics have reduced anaesthetic risks considerably but as with all operations, general anaesthesia does carry some risk, albeit small. 

Sometimes following surgery there is a lack of bowel control for a few weeks due to damage to some of the small nerves surrounding the sacs. However this is a rare complication and in the majority of cases resolves without further treatment.  In chronic cases of anal impaction or infection removal of the anal sacs is the only permanent cure.

My dog is very nervous and sometimes seems to express his own glands.  Is this normal?

It is quite common for dogs to express their anal sacs, particularly if frightened. Some dogs even appear to lack control of the anus or anal sac ducts so that small quantities of fluid will drain out when they are resting. This, of course, leaves an unpleasant lingering odour in the home. This is another indication for surgical removal.

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