What is Perianal Fistula?
Tunnel-like formations in your dog’s skin and deeper tissues in the surrounding area of your dog’s anus are called perianal fistulas. These lesions can be minor or more serious; they begin as small holes in your dog’s skin and then can become wide and deep and can ultimately surround your dog’s anus in its entirety. This condition is most likely to occur in German Shepherds, though it can happen in any breed.
Perianal fistulas can cause a great deal of pain and discomfort in your dog. Dogs that experience a perianal fistula may also have chronic diarrhea as a result of inflammatory bowel disease; it is thought that these two conditions may be connected.
Perianal fistula, which is also known as anal furunculosis, occurs when a dog experiences chronic lesions around their anus that worsen, leading to deep ulcers that drain and are painful to the dog.
Symptoms of Perianal Fistula in Dogs
Should your dog have a perianal fistula, you may observe the following:
- He is experiencing pain when defecating
- He is struggling to defecate
- He is constipated and/or experiencing diarrhea
- Mucus or blood in his stools
- Extensive licking and biting of his anus
- He may appear restless and cry out when he is about to have a bowel movement.
- Should you try to lift his tail he may struggle or bite.
- Low tail carriage
- A foul smell
- Irritability and even aggression can occur due to the severe pain dogs can experience
Types
A dog can experience a mild perianal fistula or his condition may be moderate or severe.
Causes of Perianal Fistula in Dogs
The exact reason that perianal fistulas occur is not fully understood. It is thought that the condition begins as inflammation of the sweat and oil glands that are in and around your dog’s anus. This then results in an infection of the area, which can then lead to abscesses that open and drain. The area under the tail and around the anus is warm and moist, which makes it easy for bacteria to multiply.
While perianal fistulas most often affect German Shepherds, they can occur in any breed of dog. German Shepherds often carry their heavy tail low between their hip bones, which will cover their anus; it is thought this may predispose them to this condition. Because German Shepherds are more often affected, genetics may play a role in the condition developing.
Diagnosis of Perianal Fistula in Dogs
Should you notice any of these symptoms in your dog, you will want to schedule an appointment with your veterinarian. In addition to asking you for information regarding the symptoms you have seen in your dog and when you first noticed them, your veterinarian will conduct a physical examination. This will include a rectal exam because perianal fistulas may be caused by an infection or blockage of the anal sacs. Some dogs will need to be sedated in order for the exam to be conducted. Your veterinarian will obtain samples of cells or tissues from the anal sacs or fistula which can be looked at under a microscope or used for bacterial culture and sensitivity testing.
Treatment of Perianal Fistula in Dogs
Your veterinarian will likely consider providing both medical and surgical treatments as 80% of those experiencing perianal fistulas will experience a recurrence of the condition. When the condition is relatively mild, your veterinarian may clip any hair in the anal area and cleanse the area with an antiseptic solution and then flush the area with water. Should the condition be more severe, treatment options include:
- Modifications in your dog’s diet (a novel protein diet)
- Antibiotics (for example metronidazole)
- A combination of oral cyclosporine and ketoconazole
- Administration of oral anti-inflammatory and immunosuppressive medications like prednisone (this has been less effective than cyclosporine and ketoconazole)
- Topical immunosuppressive medications
Treatment will usually take place for 7-9 weeks, though recurrence is typical once treatment is stopped, particularly in dogs with moderate disease.
Your veterinarian may also consider surgical treatment which will include removing any affected tissue, whether through freezing it, cautery or laser surgery. Anal sacs may also be removed during surgery. In some cases, the veterinarian may recommend removing the tail as it may help with keeping the area clean and aerated, which will assist with healing of current fistulas and decrease the chance that the condition will recur; this is done less often today.
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Recovery of Perianal Fistula in Dogs
Should a dog undergo cryosurgery or laser surgery he will have open wounds for a few weeks. These will need to be cleaned daily and dead tissue, bacterial and fecal material will have to be removed. Your veterinarian will likely recommend that your dog take stool softeners to help your dog not experience pain when having a bowel movement. An e-collar will likely be necessary so that your dog does not cause harm to the wounds.
The condition will often have to be managed over the course of your dog’s life, through diets and medication (immune suppressants). In cases where the dog experiences chronic damage to the perianal area, whether from the fistulas or after surgeries, it can impact the area’s nerves, which can cause fecal incontinence.
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Perianal Fistula Questions and Advice from Veterinary Professionals
Australian Shepherd
Twelve Years
1 found this helpful
1 found this helpful
My pet has the following symptoms:
Scab On Butt Hole
Hey, my dog has a scab on the outside of her butthole. She's pooping fine but she has been licking it and it is raw. Thanks!
July 13, 2020
Answered by Dr. Michele K. DVM
1 Recommendations
Thank you for your question.
If the scabbed area is infected or she will not leave it alone and it becomes a problem, you may need to have her seen by a veterinarian. Unfortunately, there is not a lot that I can do over an email to heal a scab, and if it is not resolving over a day or two, it would be best to have her seen by your veterinarian. They will be able to examine her, and see what might be going on and causing it, and get any treatment that she needs. I hope that she is okay, and all goes well.
July 13, 2020
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Havanese
Peanut
3 Years
0 found this helpful
0 found this helpful
My pet has the following symptoms:
Pain
Excessive Licking
Urination Pain
hi, i have a 3.5 year old female Havanese pup who one day had an erythema on the left side of her anus one day and a big bloody vesicle the next day which had fistulized and ruptured on the way to the vets (3 centimeters diameter), the vet drained the cyst which was filled with mostly bloody discharge and i brought her home and she's wearing diaper/wound dressing now my pup refuses to drink water (24h) and has not urinated/pooped since yesterday, she's also been put on oral Amoxicillin-Clavulunate 75mg BID and topical Nitrofurazone oint which i read is not the optimal topical agent.
1. should i use topical Neosporin for her instead of Nitrofurazone?
2. should i also start her on Cyclosporine as to hasten the healing of the area since she's visibly troubled?
3. i'm changing her wound dressing twice daily, is that okay?
4. how long is it going to take for her to recover fully and be able to urinate/defecate easily?
5. should i change her diet? i feed her Royal Canine hepatic (she used to have high liver enzymes) and sometimes chicken/beef, what should i feed her now?
Sept. 8, 2018
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Boxer
ty
11 Years
0 found this helpful
0 found this helpful
My pet has the following symptoms:
Swollen Anal
I have a boxer who is 11. I notice his anal area on the right side is soft and swollen. what could this be he is not in pay no change in behavior, eating, etc. he has been lifting that rear back leg when he eats. Help! Thank you
July 16, 2018
Answered by Dr. Michele K. DVM
0 Recommendations
If Ty is lifting that leg when he is eating, there may be some sort of sensation that is bothering him with the swelling. Since I cannot examine him or see the area, it would be best to have him seen by a veterinarian, as they can look at it, do any testing that may be needed, and let you know what it is, and if any treatment is needed.
July 16, 2018
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German Shepherd Dog
Buck
3 Years
3 found this helpful
3 found this helpful
My pet has the following symptoms:
Licking And Frequent Squatting
My German Shepherd Buck is 3 and was just diagnosed with Perianal Fistulas. My vet recommended a hypoallergenic dog food along with antibiotics and steroid treatments. What exactly is the difference in this food and a regular dog food. Can I make him food myself. I saw a recipe online for a combination beef, rice and eggs. What should he NOT have?
June 5, 2018
3 Recommendations
Food allergies are a suspected cause or contributing factor in the development of perianal fistulas which is why your Veterinarian wants to move Buck away from his regular food onto a hypoallergenic diet; hydrolysed protein, new high quality protein sources (fish, venison etc…) and others may help in this regard. I understand that many owners wish to make their own food but I would encourage you to give a complete formulated food so that all nutritional requirements are met (homemade diets are not as simple as the forums suggest especially for long term issues like this). For specific information, it may be wise reaching out to a certified Veterinary Nutritionist; PetDiets have a section on their site where you may ask a Nutritionist a question if you really want a homemade diet. Regards Dr Callum Turner DVM
www.petdiets.com/Ask-the-Nutritionist
June 6, 2018
Thank you so much for this extremely helpful article. I know now that my poor shepherd Riley is suffering from this disease. I have brought him to the veterinarian 3 times in the last 4 weeks, and she never even mentioned this. The last visit my regular vet was not in,(due to a vacation) and I saw a covering vet. She immediately mentioned that his condition is most likely a perianal Fistulae. He has been on two different antibiotics. Clavimax being the current medication that he is taking. I really appreciate this article. At least now I am educated, informed, and can make a better decision on how to proceed with caring for and treating this disease. Thank you very much.
July 21, 2018
Brian L.
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