Canine Pedal Furunculosis
What is Canine Pedal Furunculosis (Interdigital pyogranuloma)?
The etiology (cause) is unclear but one theory is that sterile pedal furunculosis is a persistent, immune-mediated inflammatory response to keratin and triglycerides freed from ruptured fair follicles and glands within the skin layer. The condition is relatively uncommon in dogs, with short breeds most predisposed.
These skin lesions can manifest as single to multiple, inflamed bumps or cyst which can be firm or fluctuant, typically in-between the digits. They may be painful or itchy, ulcerative and may develop draining tracts with bacterial fluid. These lesions can spontaneously resolve, wax and wane, or persist indefinitely. Inflammation of regional lymph nodes is common but other signs throughout the body is generally not noted. Secondary infection (bacterial and fungal) is common.
The severity and reoccurrence are often worsened by underlying allergic disease like Atopic dermatitis and food allergies. Although the cause is unknown, short hairs that are forced through the follicle, creating a “sterile furuncle”, which subsequently becomes secondarily infected, seems to be the most important component of the disease. “Ingrown” hairs are a key feature of the development of this skin condition.
- Based on history, clinical examination.
- Microscopic assessment via skin cytology
- +/- cultures.
Treatment and Prognosis
- Treatment can be frustrating as pinpointing the underlying cause can be challenging. Your veterinarian will discuss the potential for allergic disease (e.g. Atopic dermatitis, food allergy), wet environment, dirt kennels, friction in short-coated breads.
- Antibiotics or antifungals are frequently required for secondary infections.
- Topical wipes (e.g. chlorhexidine-containing) are frequently incorporated as a means of topical management.
- In some cases, immunosuppressive medications (e.g. Cyclosporine/Prednisone) are utilized if the condition is suspected to be immune mediated.
- The prognosis is good to fair. Lifelong medical therapy may be required to maintain remission and scarring is relatively common in chronic cases.