Perianal Fistula in Senior German Shepherds

Updated: May 3




Perianal fistula, also known as anal furunculosis, is a serious medical condition that causes chronic inflammation and ulcerative, tunnel-like lesions of the perianal tissues surrounding a dog's anus. It starts as tiny holes in the dog's skin in the anus area and then evolves into deep tunnel-like lesions until the anus is consumed entirely. Perianal fistula is relatively common among senior German Shepherds. In fact, of all diagnosed canine perianal fistula cases, 80% are middle-aged and older German Shepherds, and most are male. Unfortunately, many German Shepherd owners are unaware of this progressive and painful disease until it's progressed.


In this #LifeWithOldDogs® blog post and podcast, we'll provide information on perianal fistula in senior German Shepherds, including what it is, the symptoms to look out for, and treatment options. By arming yourself with knowledge about perianal fistula, you can be better prepared to deal with this condition if your fur friend ever suffers from it.




What Causes Perianal Fistula?

The cause is not fully understood just yet, but one theory is that dogs with low hanging, broad, heavy tails, such as that of a German Shepherd, contribute to Perianal Fistula because the position of the tail over the anus inhibits the ability for adequate airflow in the anal region. Another possibility is the impaction, infection, or rupture of anal sacs, which are located on either side of the anus. But current studies point to perianal fistula being an auto-immune disease with genetics playing a role in who gets it and who doesn't




What Are The Signs Of Perianal Fistula?

  • Straining to defecate



  • Crying or in visible pain when defecating

  • Persistently licking the anal area

  • Biting at the anal area

  • diarrhea or constipation

  • Mucus or blood in stool

  • Loss of appetite

  • Unwilling to sit

  • Reluctance to wag his tail

  • Changes in behavior such as depression or aggression

  • Small oozing holes surrounding the anus

  • Tunnel-like formations, which can be deep

  • Pus/infection

  • Bad Smell


How Is Perianal Fistula Diagnosed?

Your veterinarian will listen to your concerns, refer to your fur friend's medical history, and perform a physical examination, including a rectal exam and a look at the anal sacs. She may also take samples of cells or tissue from the anal sacs or fistulas while performing the rectal exam for further testing. Depending on how your fur friend feels, he may need to be sedated for this examination.



Treatment for Perianal Fistula:

Since 80% of those suffering from perianal fistula will suffer from it again, treatment involves both medication and surgical tactics to ensure the best possible outcome.


Medications can include:

  • Antibiotics (such as metronidazole)

  • Cyclosporine (inhibits immune system function

  • ketoconazole (antifungal cream)

  • Prednisone

  • Topical immunosuppressant creams (Tacrolimus)

Surgery (if needed):

  • Remove affected and dead tissue

  • Possible anal sac removal

  • Repair lesions if small

The surgery method of choice is performed via laser and cryosurgery, as well as cauterization.


If surgery is performed, your fur friend will have open sores for a few weeks, which will require regular attention and care to see that they do not become infected and heal properly.



Other modalities of treatment may include:

  • Keeping hair trimmed around the anus

  • Changing diet to a novel protein diet

  • Keep area cleansed with antiseptic solution and water


(Side note: Treatment can take months to get the disease under control, and reoccurrence is typical in dogs once treatment is stopped, In 20% of dogs treatment doesn't work at all. In those cases, treatment comes down to maintaining the disease.)


Prognosis For Senior German Shepherds With Perianal Fistula:

Unfortunately, fur friends with perianal fistula require lifelong care, whether it be via a special diet, medication, additional surgeries, or fecal incontinence is