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Perianal Fistulas in Dogs: The Role of Diet

Perianal Fistulas in Dogs

If your dog was recently diagnosed with annoying perianal fistulas, you may be wondering what's the role of diet for perianal fistulas in dogs. This is a subject of interest considering the important role food may have in this condition. Interestingly, the foods that you feed your dog may certainly have an impact on this condition and therefore the topic merits further elucidation. Following is some general information concerning perianal fistulas in dogs, what they are and how affect dogs along with some details about a perianal fistula dog diet.

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Perianal Fistulas in Dogs

Also known as anal furunculosis, or perianal sinus, perianal fistula is a medical condition that may affect a variety of dogs, but certain breeds are particularly predisposed.

If there was ever a prize for the poster child for perianal fistulas in dogs, that prize would certainly go to the German Shepherd Dog. Other possible contenders would include Irish setters and several crossbreeds with some German shepherd heritage.

There appears to be some sort of connection between tail-set and the onset of perianal fistulas in dogs. Indeed, in the past, tail amputation in affected dogs was often advocated. The way the German shepherd carries the tail low between the hip bones along with the broad-based tail may be a predisposing factor. There are chances that there may also be a genetic predisposition.

But what exactly are perianal fistulas in dogs? To be graphic, the fistulas are simply holes found in the skin and underlying tissue found in the dog's perianal area (the area around the dog's anus).

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These holes may initially appear small, but as they progress, they may enlarge into tunnel-like formations causing wider and deeper holes surrounding the dog's anal area. The holes may appear ulcerated and may also drain fluid.

In the early stages, the condition may be barely noticeable and the vet during an exam may be the first to notice the signs. In other cases, it's the owner to notice the later signs once they become more pronounced and difficult to ignore, but what are the symptoms of perianal fistulas in dogs? There are several.

Symptoms of Perianal Fistulas 


Of course, as one may expect, the fistulas are known for being painful. Affected dogs may have mild discomfort to severe pain. The pain may be manifested in various ways. The dog may lick excessively under the tail, may have trouble sitting, may feel pain when moving the tail and may be prone to pain during defecation. 

On top of that, to make matters worse, dogs may also suffer from chronic diarrhea with blood and mucus from inflammatory bowel disease. It might not be a casual coincidence that both conditions appear together, there is indeed belief that there is a relationship between inflammatory bowel disease and the onset of perianal fistulas in dogs.

Overall, the symptoms put together can really put a dent in the dog's quality of life. Dog owners are often desperate to find an effective treatment to help their dogs live better. The good news is that there are several options and one of them is improving the dog's diet.

Treating Dog Perianal Fistulas

Because an exact underlying cause for perianal fistulas in dogs has not been found, treatment mostly aims at providing the dog relief. Some dog owners have noticed some improvements in clipping the hairs under the tail so to allow more ventilation.

Medical therapy may be helpful and there are several medications used. Because perianal fistulas respond to steroids and cyclosporine, which are immune suppressant drugs, the condition is thought to be caused by an autoimmune disease. In the case of secondary infections, antibiotics are used. Stool softeners may also be prescribed to help the dog cope with the painful defecation.

In cases that do not respond to medical therapy or recurrent, severe cases, surgical intervention may be needed and i may involve removing, dead, damaged and infected tissues (a procedure medically known as debridement) along with cryotherapy to allow the tissue to heal. However, results can be disappointing and the fissures may recur sometimes even causing complications such as fecal incontinence.

Recent studies have shown success with topical tacrolimus 0.1% ointment along with prednisone, metronidazole and a novel protein diet. 

The Role of Diet

pros and cons of raw diet for dogs

Dietary changes may be helpful in dogs suffering from fistulas due to a suspected association between perianal fistulae and food allergies. Veterinarian Dr. Welton, believes that a hypoallergenic diet can potentially be beneficial in dogs suffering from perianal fistulas, and while yes, grains must be eliminated, it's also important that the most common protein allergens are eliminated too. The most common protein allergens include beef, chicken and eggs.

This means that affected dogs should be placed on a diet containing a novel protein source, one that the dog has never been exposed to before. Here comes the role of dog foods containing new proteins deriving from unusual meat sources such as venison, duck, rabbit and bison. Another option for dog allergies to meat protein is feeding dogs hydrolyzed protein diets. Consult with your vet for specific dietary recommendations.

It's also important feeding a diet that causes the stools to be softer and smaller so to minimize the chances for painful defecation. Veterinarian Dr. Michael Salkin suggests avoiding the high fiber diets which cause the dog to produce bulky stools and instead opt for the high digestible foods that are categorized as 'low residue.' Such a diet may help and it may be worthy consulting with a veterinary nutritionist to have the diet specifically customized to meet the individual needs of the dog.

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  • Long-term prospective evaluation of topically applied 0.1% tacrolimus ointment for treatment of perianal sinuses in dogs. J Am Vet Med Assoc. August 2009;235(4):397-404. Bryden J Stanley1; Joe G Hauptman 1Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, USA
  • DVM360: Medical management of perianal fistula

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