Anal Furunculosis


Why Should I bring my Pet to Willows for Anal Furunculosis?

Willows is one of Europe’s leading small animal referral centres. Our state-of-the-art hospital is led by internationally renowned Specialists who are committed to providing the highest standards of veterinary care.

Willows Skin and Ear Clinic is led by Drs Richard Harvey and Tania Nunes Rodrigues, European Specialists in Veterinary Dermatology who have extensive experience of diagnosing and managing cases of anal furunculosis.

As one of only referral hospitals in the UK to be home to two European Specialists in Veterinary Dermatology our Skin and Ear experts are supported by our multidisciplinary team of Specialists across a number of disciplines including Anaesthesia and Diagnostic Imaging. In addition, Willows has a large, dedicated team of Nurses and clinical support staff available 24 hours a day, every day of the year to provide round-the-clock care for your pet.

What is Anal Furunculosis?

Anal furunculosis is a chronic, progressive inflammatory disease of dogs that results in ulceration and inflammation in the area surrounding the anus. Anal furunculosis occurs most commonly in middle aged or old aged German shepherd dogs, although other breeds can be affected.

What Causes Anal Furunculosis?

There are a number of theories regarding the cause(s) of anal furunculosis. These include the presence of a wide-based tail and increased numbers of sweat glands in the region of the anal canal. However, recent research has found a number of similarities between anal furunculosis in dogs and Crohn’s disease in humans. Analysis suggests that anal furunculosis lesions develop due to a lack of some of the immune system’s defences that would usually protect the intestines and perineal skin from the bacteria normally present in that area. A separate part of the immune system is then exposed to more bacteria than normal and becomes over-activated. This over-activation of certain components of the immune system leads to marked inflammation and ulceration of the local area.


How is Anal Furunculosis Diagnosed?

Anal furunculosis is usually diagnosed by clinical examination. Clinical signs include pain, sometimes extreme, whilst trying to pass faeces, there may be an unpleasant odour around the bottom and the hair may be matted around the anus.

Misdiagnoses are most often sinus formation secondary to anal sac infection and rupture and are an immune-mediated disease known as mucocutaneous lupus erythematosus.

Close examination to define the diagnosis may require sedation or general anaesthesia as, understandably, it can be a little uncomfortable. This also allows thorough clipping of the hair surrounding the lesions, as well as cleaning of the area and documentation of the extent and distribution of the lesions. This initial assessment is invaluable in allowing monitoring of progress during subsequent treatment.

What Treatments are Available for Anal Furunculosis?

Currently, the treatment of choice for anal furunculosis involved drug therapy using  ciclosporin. In the majority of cases this will shrink the lesions and may clear them up completely, however some dogs do require two or three times the standard dose. In persistent cases, the option of surgery to remove the remaining ulcerated areas may be discussed.

What can I Expect if my Dog is Diagnosed with Anal Furunculosis?

At least 95% of cases will significantly improve following medical therapy, with lesions reducing in size between 60% and 100%. Drug therapy usually lasts from 4-24 weeks with most patients responding within 12 weeks. Up to 85% of patients go into complete remission (lesions disappear) using medical therapy, however, approximately 40% of these cases can suffer recurrence of the disease. If recurrence occurs it usually does so within six to eight months after treatment is stopped. Patients suffering from recurrence often respond to additional courses of medical therapy. Approximately 4% of cases do not significantly improve with medical therapy.

Surgery is generally reserved for cases that continue to suffer from lesions despite medical therapy or those with frequent recurrences. Surgery is performed once the lesions are small enough to avoid the need for reconstructive skin closure techniques (plastic surgery). The success rates after surgery vary, however recent work suggests that in appropriately managed cases, 90% of dogs are cured. To achieve these success rates, careful patient management is required and usually involves a period of lesion reduction using medication prior to surgery.

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To assist owners whose pets have skin and ear conditions, we have put together a range of information pages to talk you through some of the more common dermatology conditions seen by our Specialist team.