Causes of Canine Anal Sac Disease
The underlying causes of anal sac problems are not fully understood. Several predisposing factors have been suggested, including obesity, bouts of diarrhea, poor muscle tone around the anus, chronically soft feces and excessive or retained anal glandular secretions. Normally, the paired anal sacs act as reservoirs for secretions from the glandular tissue that lines them. Changes in the amount or character of those secretions, or changes in muscle tone or the consistency of a dog’s stool, can plug the anal sacs and cause them to overfill, sometimes to the point of rupturing. This causes pressure, inflammation and irritation. It also promotes abnormal overgrowth of bacteria that normally are present inside the sacs, which in turn increases the chances of infection, impaction and formation of pus-filled abscesses. Both benign and malignant tumors of the anal sacs can also occur, causing symptoms similar if not identical to those caused by more temporary and treatable problems. Why tumors develop in the area around the anus (the “perianal” area) is not known, but they are fairly common in domestic dogs.
Prevention of Anal Sac Disease
One of the best ways to prevent anal sac disease is to feed dogs a high quality diet that is low in saturated fats and has enough indigestible dietary fiber to reduce the frequency of loose or sloppy stools and increase fecal bulk. Anal sac secretions can’t be evacuated naturally unless there is a sufficient amount of firm, formed feces passing through a dog’s rectum. Obese or overweight dogs should be put on a weight loss regimen, because excess weight has been associated with anal sac problems. Routine manual expression of the anal sacs by veterinarians, veterinary technicians, groomers or owners should not be necessary in normal dogs. In fact, chronic manipulation of the anal sacs can damage their sensitive tissues and increase the risk of more serious problems. However, in certain situations, it may become necessary to manually express a dog’s anal glands. Good routine hygiene can help prevent the accumulation of bacteria and other infectious microorganisms around the anal area. Unfortunately, given the current state of medical knowledge, there is no way to prevent perianal tumors. Research into the causes and treatment of cancer remains in the forefront of both human and veterinary medicine. A veterinarian is the best person to assess a particular dog’s anal sac health and discuss appropriate management protocols with its owner.