Canker is a chronic hypertrophy and apparent suppuration of the horn-producing tissues of the foot, involving the frog and the sole. The cause is unknown. Although frequently described as a disease seen in animals kept in moist or unsanitary environments, it is also encountered in well-cared-for animals. The disease can be observed in both front- and hindfeet. The disease most commonly starts in the caudal frog, where the affected area consists of an inflamed granulation tissue with proliferative epithelium, often appearing as fronds. The affected tissue is commonly covered by caseous exudate, which may be foul smelling. The surface of the lesion is irregular with a characteristic, cauliflower-like vegetative growth. The disease process may extend to the sole and even to the wall, showing no tendency to heal.
Treatment requires radical debridement down to normal corium, using either sharp debridement or electrocautery. All loose horn and affected tissue should be removed. If sharp debridement is used, cryotherapy can be applied subsequently to kill affected tissue not removed by sharp debridement. Following debridement, an antiseptic or antibiotic dressing should be applied daily; good results have been reported using a solution of benzoyl peroxide dissolved in acetone. Metronidazole is commonly applied topically. A clean, dry wound environment must be maintained to allow healing, which may take weeks or months. Waterproof materials and plastic boots are used for such purposes.
Last full review/revision March 2012 by Stephen B. Adams, DVM, MS, DACVS; Andrew L. Crawford, BVetMed, CertES (Orth), MRCVS; James K. Belknap, DVM, PhD, DACVS; Jane C. Boswell, MA, VetMB, CertVA, CertES (Orth), DECVS, MRCVS; Peter Clegg, MA, Vet MB, PhD, CertEO, DECVS, MRCVS; Marcus J. Head, BVetMed, MRCVS; C. Wayne McIlwraith, BVSc, PhD, DSc, FRCVS, DACVS; James Schumacher, DVM, MS, DACVS, MRCVS; John Schumacher, DVM, MS, DACVS, MRCVS; Roger K. W. Smith, MA, VetMB, PhD, DEO, DECVS, MRCVS; Chris Whitton, BVSc, FACVSc, PhD; Jean-Marie Denoix, DVM, PhD, Agregé; Joerg A. Auer, DrMedVet, Dr h c, MS, DACVS, DECVS