The cause of perianal fistulas remains unclear, but it is believed to be immune mediated or related to reaction from some food allergens. Some believe that it is related to a form of colitis. Therefore, it is advisable to find underlying cause. If there are no causes determined, the medical management using immunosuppressive drugs such as cyclosporine or prednisone found to be encouraging. Azathioprine, another potent immunosuppressive agent, may be tried if prednisone or cyclosporine is unsuccessful. Surgery is now usually reserved for cases that involve the anal sacs or for selective fistulas that do not respond to medical management. Your vet may advise food trial using novel proteins which your pet has not been exposed. Likewise your vet can conduct neurological examination to assess bladder and bowel control.
Question by - Rama Iyer, Bangalore