The anal sacs of dogs and cats exist in the rectum, approximately 1/2 to 1 inch from the opening of the anus. They are often misnamed the anal glands, but this is incorrect. The anal sacs are stuctures that collect fluid secreted by the anal glands. As the feces passes through the anal opening upon defecation, the sacs are expressed. and the fluid coats the feces giving it a scent distinct to the animal.
Occasionally in dogs and cats, (more commonly in dogs), the anal sacs do not effectively express, and the fluid collects excessivley in the anal sacs. This causes discomfort and irritation in the anal area. This discomfort leads the animal to lick the area excessively or even exhibit scooting behavior (walking with the front legs while dragging the anus on the floor).
If the sacs remain full for too long, an infection can develop, which can be quite severe and painful. Treatment consists of manually expressing the anal sacs periodically as needed. If the sacs are infected,
Then oral antibiotics should be administered in addition to having the anal sacs manually expressed. In severe infections, the anal sacs may need to be infused with antibiotic ointment.
If anal sac impactions and/or infections become frequent, a surgical procedure can be performed whereby the anal sacs are removed, known as an anal sacculectomy. A rare complication of the procedure is stool incontinence, but in the hands of a surgeon with substantial experience with anal sacculectomy, this type of complication is exceedingly rare.
Roger L. Welton, DVM
Founder and Chief Editor, Web-DVM.net
President, Maybeck Animal Hospital
Article updated 9/3/2012