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Perianal Fistulae in Dogs
- Perianal fistulae are abnormal openings in the skin around the anus that are painful and do not heal on their own.
- This condition occurs most commonly in German shepherds.
- Signs include ulcerated, draining tracts around the anus, difficulty passing feces, reluctance to sit, rectal odor, and loss of appetite.
- Although the exact cause is unknown, it is suspected to be an immune system disorder.
- Tail shape or conformation may contribute to the problem.
- Diagnosis is usually made by examination, but a biopsy (tissue sample) provides a definitive diagnosis.
- Treatment may require oral and topical immune suppressants, antibiotics, and a hypoallergenic diet.
- In severe cases, surgery may be necessary.
- It may take several months to resolve the lesions, and many dogs require some type of therapy for the rest of their lives.
What Are Perianal Fistulae?
Perianal fistulae are draining openings in the skin around the anus that do not heal. The word fistulae is the plural of fistula, which is an abnormal tract or passageway from an abscess, organ, or body cavity to the body surface. The term perianal describes the area around the anus.
This chronic, inflammatory, and painful condition occurs most often in German shepherds, but Irish setters and other breeds can also develop it. Middle-aged to older dogs are more likely to be affected.
What Are the Signs of Perianal Fistulae?
Signs of perianal fistulae include:
- Ulcerated, draining tracts around the anal area
- Rectal odor
- Difficulty passing feces, constipation
- Straining to pass feces
- Painful when sitting, or reluctance to sit
- Bloody stools, diarrhea, or fecal incontinence
- Appetite loss and weight loss
- Excessive licking or grooming around the anal area
What Causes This Condition?
The exact cause of this condition is unknown, although it is suspected to be an immune system disorder.
A dog’s physical conformation may also contribute to the disease. For example, when dogs hold their tails low against the back of their bodies, like German shepherds often do, it may prevent the anal area from getting proper ventilation and may encourage the buildup of feces in the area.
How Is This Condition Diagnosed?
A veterinarian will usually make the diagnosis based on examining the area. However, a biopsy (tissue sample) is required for a definitive diagnosis.
How Are Perianal Fistulae Treated?
Treatment may include oral and topical medications to suppress the immune system, as well as antibiotics. Stool softeners may also be prescribed to reduce pain during defecation.
If a food allergy is suspected, a hypoallergenic diet may be recommended. When the dog is on this diet, it is important that he or she receives no other foods or treats, including rawhide bones.
Since it may take several months before the lesions are under control, periodic recheck appointments with your veterinarian are usually recommended. Many dogs require some kind of treatment for the rest of their lives.
If the lesions do not resolve, or if they recur, surgery may be necessary to remove the diseased tissue. At the same time, the anal sacs, located near the anus, may also be removed. In some cases, tail amputation can help improve ventilation and cleanliness and help control the problem.