Managing Anal Furunculosis in Dogs

CE Canine anal furunculosis (perianal fistula) is a chronic disease of the perianal, anal, and/or rectal tissue characterized by the presence of ulcerative tracts.The specific cause of this debilitating disease is unknown and continues to be controversial. Nevertheless, a multifactorial immune-mediated mechanism is suspected. Diagnosis is usually straightforward in German shepherds presenting with perianal lesions and associated clinical signs. Although canine anal furunculosis was once considered a primary surgical disease, medical management is now the initial treatment of choice. Management includes immunosuppressive, hygiene, and dietary therapy. It is critical to inform clients of the relapsing and remitting course of this inflammatory disease. clude Irish setters, collies, Border collies, Old English sheepdogs, Labrador retrievers, English bulldogs, beagles, Bouvier des Flandres, spaniels, and mixed breeds. The disease usually affects middle-aged dogs; the mean age is reportedly 4 to 7 years. A sex predilection has not been definitively described. Clinical signs prompting veterinary care are listed in the box on page 342. The anatomy of the anal region is described in the other box on page 342. Considering the lack of success with previous therapies, many owners have low expectations in treating canine anal furunculosis. PATHOGENESIS A definitive cause of anal furunculosis has not been described; however, many theories have been proposed. The more common hypotheses have included poor conformation of the perianal region and tail (i.e., broad-based low tail carriage), anal crypt fecalith impaction resulting in abscessation, spread of infection from the anal glands or anal sacs, trauma, and foreign body reaction. Unfortunately, little evidence supports May 2005 339 COMPENDIUM Managing Anal Furunculosis in Dogs Adam P. Patterson, DVM Karen L. Campbell, DVM,MS, DACVIM, DACVD University of Illinois at Urbana-Champaign