The anal sacs (also called anal glands) are two small pockets located just inside the anus, on the left and right sides of the anal canal in dogs and cats. Normally they produce a smelly, clear to light yellow liquid secretion, which is expressed from two small pores when the animal defecates. They can also discharge this odorous secretion spontaneously, or when the dog or cat is startled, injured, or excited.
Several different types of problems can arise from the anal sacs. These include inflammation, infection, and even tumor formation.Dogs, especially small breeds, are more commonly affected than cats. The most common anal sac problems are:
- Impaction—failure of the anal sacs to discharge, resulting in inspissation (drying out and hardening) of the contents, which then accumulate, causing discomfort as for hemorrhoids in people.
- Abscessation—bacterial infection of the sacs, usually following an impaction. Inflammation and pain in the area will be present. The abscess can often burst through the sac, draining pus and blood onto the skin and hair coat around the anus.
The diagnosis of anal sac disease is made based on history (what you have observed as your pet’s symptoms) and the physical exam performed by the veterinarian.
In terms of symptoms, dogs with anal sac impaction or abscessation are often reported to“scoot,” meaning they drag their rear end across a floor or carpet by pulling themselves along with their front legs while sitting upright. They also may attempt to lick the area frequently or seem “bothered” by discomfort. You might notice a change in their stool habits. This can be either a variation in the shape of the feces (thin, like a ribbon) or pain when attempting to defecate.