What is an anal fistula?
The term fistula refers to the formation of an abnormal "path" between two organs or between an internal organ and the skin.
In the case of a perianal fistula, an abnormal communication is created between the anal canal and the dog's skin. Fistulous lesions therefore form at the margins of the dog's anus.
Perianal fistulas: what are they due to?
A perianal fistula can form secondary to the presence of an abscess of the anal sacs or an abscessed tumor in the perianal region of the dog.
But it can also form in the absence of an abscess due to a dysfunction of the dog's immune system, a food allergy and/or a racial predisposition. Thus, the dog breeds most affected by the formation of perianal fistulas are the German Shepherd (in 80% of cases) and the Irish Setter.
Anal fistulas in dogs: symptoms
Perianal fistulas are small holes that form around the dog's anus. These lesions are covered with a muco-purulent exudate (they ooze), which usually smells very bad and sometimes contains blood.
As these fistulas are very painful for the dog, they are most often accompanied by:
- biting and licking the dog's perianal region,
- tenesmus (painful tension in the anus) and difficulty during defecation,
- the sign of the sled (the dog rubs its hindquarters leaving it on the ground while advancing with the help of its front legs),
- of anorexia,
- depression.
Their existence can also be accompanied by diarrhea or constipation as well as the presence of red blood in the stools (hematochezia).
The risk, in case of perianal fistulas in dogs, is that they become superinfected. The lesions may also extend to the base of the tail and induce necrosis of surrounding tissues.
Diagnosis and treatment of perianal fistulas in dogs
The diagnosis of perianal fistula is generally established by the veterinarian during an auscultation of the dog. In some cases, the veterinarian may need to perform an examination of the dog under anesthesia to assess the depth of the fistulas.
The treatment is generally medical, initially, then surgical if the medical treatment is not sufficiently effective.
Medical treatment of perianal fistula in dogs
In the case of perianal fistulas not caused by an abscess, the medical treatment is based on:
- the use of oral and local immunosuppressive drugs. It can generally be cyclosporin A coupled with ketoconazole or corticosteroids at immunosuppressive doses in the first case and tracrolimus ointment in the second,
- a mowing of the perianal region and the use of local antiseptic care such as antibiotic ointments,
- systemic antibiotic therapy, in case of bacterial superinfection associated with fistulas.
In parallel with this medical treatment, it is also recommended to change the dog's diet to a hypoallergenic and/or hyperdigestible or even slightly laxative diet to promote the elimination of stools.
Several weeks of treatment are generally necessary and the treatment should be continued for several weeks after the disappearance of the lesions in order to avoid recurrences.
Surgical treatment of perianal fistula in dogs
When medical treatment is ineffective, the veterinarian may then consider resorting to surgical treatment to remove the affected tissues and, if necessary, the dog's anal sacs.
It is common to have several surgeries a few months apart.
In all cases, the dog should be monitored and monitored regularly by a veterinarian to monitor the effectiveness of the treatment and avoid relapses.