Chronic Inflammation of the Anus in Dogs

If you notice that your dog is having trouble moving his bowels because he is straining or whining while defecating, you may want to check and see if there are any weeping sores around his anal area. If you see evidence of these fistulas or if you are not sure, set an appointment with your veterinarian as soon as you can. Perianal fistula disorder is a painful condition that can cause your dog to refuse to have a bowel movement until it causes an even worse condition, such as impacted bowels. Going without treatment can cause an infection and a lower quality of life for your dog.

Some experts claim that perianal fistulas are caused when the heat, moisture, and bacteria of the anal area cause sweat and oil glands to become infected, producing abscesses. The abscesses open up and drain, causing pain and further infection, leading to more fistulas that do not heal. Your dog may have only one fistula or several, but no matter how many there are it is still a painful condition that makes your dog miserable. Perianal fistula disorder starts out as small weeping holes in the skin that become wider and deeper over time until they surround the entire anal opening. Even though any breed of dog can get perianal fistula disorder, it is most common in German Shepherd dogs for an unknown reason, but it is thought to be a genetic disposition. There are several other breeds that are predisposed to perianal fistula disorder as well.

Chronic inflammation of the anus, or perianal fistula disorder, is a frustrating disorder in which there are painful holes in the skin around the anus. A fistula is described as a passage between a hollow tube (the anus) and the surface of the body. These fistulas are openings that are like tunnels surrounding the anus that never heal properly and cause serious pain and irritation for your dog, especially when he is trying to have a bowel movement.

The symptoms of perianal fistula disorder can mimic many other conditions, such as a stomach ailment or anal sac disorder. The most important thing to watch for is crying when having a bowel movement, because this means they are having pain when defecating. Some other symptoms of perianal fistula disorder are:

• Struggling to have a bowel movement
• Frequently trying to have a bowel movement
• Bad smelling anal discharge
• Excessive biting and licking the anal area 
• Growling or biting when you lift their tail
• Diarrhea
• Constipation
• Bloody feces
• Mucus in stool
• Matted hair in the anal area
• Behavior changes
• Weakness
• Weight loss
• Inability to control the bowels

Although the cause of perianal fistula disorder is not clear, the problem happens more often in older dogs (over 7 years old) of these breeds:

• German Shepherd
• Cocker Spaniel
• Cavalier King Charles Spaniel
• Brittany Springer Spaniel
• English Springer Spaniel
• Labrador Retriever
• Golden Retriever
• Border Collie
• English Sheepdog
• French Bulldog
• English Bulldog
• Irish Setter
• Some experts think it may be immune related
• It may also be the shape and heaviness of the tail trapping in bacteria and heat
• Allergic skin reaction is also a possibility

You will need to provide the veterinarian with as much of your dog’s medical history as you know, which will include illnesses, vaccine records, any changes in behavior, any new food or treats, what symptoms you have seen, and whether they have gotten worse. In addition, the veterinarian will need to do a physical examination including weight, body temperature, heart rate, blood pressure, and a rectal examination. They will need to get a rectal swab to run a bacterial and fungal culture to rule out any underlying disease or disorder that could be causing the fistula. Your dog will probably be anesthetized or sedated for the rectal examination because it may be uncomfortable.

Other tests that will be done at this time include urinalysis, complete blood count (CBC), fecal examination, and a glucose test for diabetes. The veterinarian may also need a blood gas and chemistry panel, which checks levels of calcium, potassium, creatinine, phosphate, and urea. A digital radiograph (x-ray) will also be used to be sure there are no tumors or other internal injuries causing the problem. Additionally, the veterinarian should do a fine needle biopsy (cytology) to test the cells or tissues of the affected area.

Perianal fistula disorder is hard to treat and can be very aggravating for both you and your dog. It is also difficult for your veterinarian when the symptoms do not go away or if they go away and then return after several months of symptom-free treatment. Be prepared for an ongoing process that you may have to deal with for the rest of your dog’s life.

Perianal fistula disorder can be treated with medicine or surgery. The medication most often used for perianal fistula disorder is cyclosporine, which is an immunosuppressant that allows the fistula to heal. Cyclosporine usually takes from one to three months to reduce the size of the fistula if it is going to work. This drug does not work for all dogs and it is expensive, but it is usually the best course for your dog. Surgical ablation of the fistula is not as effective as the medication and it has the risks that all surgeries do, so the surgery is usually not done unless the medication is not working after a certain amount of time.

No matter what treatment you choose, this disorder is a tough one to treat. Even though it is not life threatening, it does reduce your dog’s quality of life so it is essential to get treatment as soon as possible if you suspect your dog has perianal fistula disorder. The earlier the treatment the better the chances for successful recovery. You will have to bring your dog in for several follow-up visits with the veterinarian to see if the medication is working or if the surgery has done what it is supposed to do.

The veterinarian will prescribe a mild hypoallergenic diet with stool softener and antibiotics if necessary. Be sure to follow all of your veterinarian’s instructions and follow up when instructed.