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15 December 2012

Anal Furunculosis In The Dog, Cause, Treatment, Prognosis.

anal furunculosis dog german shepherd

{ This disease is also called perianal fistula . }


What is Anal Furunculosis? :  This is a disease most frequently seen in the German Shepherd but it can sometimes occur in other breeds but this is very rare.
The disease is characterised by chronic infection and ulceration of the area around the anus. More importantly there are often unseen but deeply infiltrating fistulous tracts which under run the skin. Above is a typical photo of this condition, it can actually get much worse than this ...

What causes this disease? : The precise cause of the disease is unclear but it is probably the result of several factors. The conformation of the German Shepherd allows the broad base of the tail to remain in almost continual contact with the anus and is responsible for spreading a thin film of faeces over the perineal region and over time this can cause a chronic skin infection. Some German Shepherds are unable to resist even minor superficial infections which can arise in the skin due to this sort of contamination.The anal sacs (scent glands) seem to have only secondary importance in causing the disease but they may need to be removed if they are involved in the lesions. It should be emphasised that a dog's predisposition to anal furunculosis is lifelong and relapses after an apparent cure can occur.
What are the consequences of anal furunculosis? : Many dogs with this disease will show few signs apart from licking in the anal region but in advanced cases there may be damage and scarring of the muscle around the anus which prevents normal dilation of the anus. These dogs often have difficultly and pain when passing faeces. Other dogs with more severe anal furunculosis may not be able to close the anus properly and become incontinent.
What is the treatment? The bottom line is that no single technique has been shown to result in a consistent cure. Nevertheless, in the past surgical removal of the infected tissue followed by cryo-surgery of the residual tissue without reconstruction of the surrounding skin has been met with very worthwhile results in my clinic. Another surgical technique is the rectal pull through operation which again is meeting with some success in advanced cases. However we are now getting good results using a drug called Atopica { cyclosporine } which may be used alone or in combination with another drug called ketaconazole. 

Link to the use of Atopica In The Dog.

Cyclosporine can have side effects so the treatment has to be monitored with blood tests etc. another drawback of this therapy is that cyclosporine is a very expensive drug but its use may avoid extensive painful surgery.In South Africa tail amputation has been used to treat this condition but with variable results.

What is the prognosis? : Lesions will eventually resolve in more than three quarters of those dogs that receive treatment. Some of these dogs however will need more than one course of treatment so it is vitally important that they are re-presented regularly for the follow-up surgery to minimise the risk of a relapse.
Regrettably a proportion of dogs do not respond to surgery and continue to have problems even after multiple treatments. It is difficult to predict the course for dogs with anal furunculosis that are untreated. Some remain static for long periods whilst others deteriorate rapidly ...