May 25

Written by: Surgi-Care Center for Horses
5/25/2011 3:27 PM 

Canker is an infection of the horn producing tissues of the foot. The infection begins in the frog. It can affect the sole, hoof wall, and bars of the foot as well. Although it most commonly affects draft breeds, any breed of horse can develop canker.  One or more feet can be affected. Canker is frequently seen in the Southeastern US, and may be more frequently diagnosed from July to December.

Clinical signs associated with canker include a foul odor and white finger-like projections over the frog that looks like cauliflower. These projections may be covered with pus like material. When this tissue is scratched off, it bleeds easily and may be very painful. The degree of lameness present may be related to the amount of tissue infected. Canker has to be differentiated from thrush. Thrush is a process where cells die, which affects the grooves and base of the frog. Canker can affect any part of the frog and is a process where cells rapidly grow.

The cause of canker is unknown. Predisposing factors include a wet, unhygienic environment. However, canker can occur in horses that live in clean, dry environments and have their feet trimmed at consistent interval.

Diagnosis of canker can be made either by visualizing the white finger-like projections in the region of the frog or a biopsy can be performed. The biopsy results of a canker lesion would indicate a chronic, hypertrophic, moist dermatitis of the frog. The area can be cultured, but a mixture of environmental organisms along with anaerobic bacteria is often retrieved.

Treatment of canker is best performed early in the disease process. Surgical removal of the canker should be performed. This can be done under general anesthesia or regional anesthesia. A tourniquet should be applied to the limb because the area being debrided is highly vascular. Cryotherapy, using liquid nitrogen or coolant spray, should be utilized following debridement. Topical medication should then be applied to debrided area daily. Crushed up Metronidazole tabs and a acetone and 10% benzoyl peroxide solution mixed on gauze 4x4s is a suggested treatment for canker. Metronidazole is an antibiotic, which is good for anaerobic infections. The acetone and benzoyl peroxide solution acts to dry out the affected area. It is essential to keep the horse in a dry environment during and following recovery from canker. Contact your veterinarian if you have any questions or concerns about canker.

Contact Surgi-Care Center for Horses at 813-643-7177 or email lkuebelbeck@surgi-carecenter.com with any questions regarding this topic.