Perianal fistulas (fissures) are pus-filled, tunnel-like lesions that can form in the anal cavity and spread to the skin area around the anus in dogs. Perianal fistulas cause severe pain and can greatly reduce the quality of life for your dog.
Although any dog can suffer from perianal fistulas, the American College of Veterinary Surgeons estimates that 80 percent of cases appear in German shepherds.
Your dog may experience diarrhea or constipation. You may also notice blood or mucus in the dog's stool and excessive licking and biting around the tail area. Often, dogs affected with perianal fissures will cry out painfully during defecation.
You may notice small oozing holes around the anal area. As the disease progresses, these holes become larger and break open, causing oozing sores covering the anal area. Since the fissures begin deep in the anal cavity, they can cause severe damage to the anus.
Medical treatment includes oral antibiotics, oral anti-inflammatory and immunosuppressive medication (prednisone), and topical immunosuppressive ointment, such as tacrolimus. Surgery is often necessary to remove necrotic (dead) tissue.
Perianal fissures may require lifelong care, as they often return even after treatment. Damage to the nerves around the anus may lead to fecal incontinence. Unfortunately, there is no way to prevent perianal fissures. A high-quality diet, though, may be beneficial.