Corns

Summary

Corns (also referred to as keratomas, footpad keratosis, and orthokeratotic hyperkeratosis) may seem like a minor nuisance, but as any human who’s suffered them can attest, they can lead to excruciating discomfort and persistent lameness.

Common to certain breeds of dogs (sighthounds, in particular), there are three major theories for the development of these firm, deep, well-circumscribed lesions located within the digital pads of the feet:

Foreign bodies: These may lead to scar tissue development at the site.
Papilloma virus infection: This virus may cause wart-like lesions elsewhere in the body, but on the foot, these may get pushed into deeper layers because of the constant pressure applied to the area.
Pressure and abrasion: Chronic trauma related to pressure and abrasion may be responsible as well. This may explain why racing greyhounds are highly predisposed to this condition.

Symptoms and Identification

The clinical signs of corns are fairly obvious. Lameness is the most typical sign, especially when walking or running on hard surfaces, but visual inspection of the foot and a painful reaction to pressure at the site is typically required to reach a more definitive diagnosis.

Sometimes, the claws on the affected foot (or sometimes multiple feet) may be longer than others, a typical sign that the dog is attempting to apply less pressure to their painful pads.

Affected Breeds

All breeds of dogs are susceptible to corns, but the sighthound family of dogs (and greyhounds in particular) are considered highly predisposed.

Treatment

The ideal treatment of corns typically involves their surgical removal (though a great many methods have been described and few studied in much detail). However, preventing digital pad pressure during healing is a requirement. Placing pressure bandages, special padding and booties are often part of the process.

Novel treatments for preventing local pressure on the area as it heals are currently being developed. In particular, injecting liquid silicone under corns has resulted in plantar pressure relief in the case of humans. A modification of this technique is currently being studied in dogs.

Veterinary Cost

The cost of corns depends on the approach to treatment. Anesthesia, surgical removal and follow-up bandage placement may cost upwards of $1,000 per corn. This, of course, will vary depending on geographic locale and whether a board-certified surgeon is elected for treatment of the condition.

Prevention

Because we’re not sure what leads to corn development, prevention of corns is typically not considered feasible. For predisposed dogs, however, the use of padded, pressure-relieving booties may be helpful, especially when walking on hard surfaces.

References

Andelman NC. Dermatology. In: Bloomberg MS, Dee JF, Taylor RA, eds. Canine sports medicine and surgery. Philadelphia, Pa: WB Saunders Co, 1998;35-44.

Balara JM, McCarthy RJ, Kiupel M, et al. Clinical, histologic, and immunohistochemical characterization of wart-like lesions on the paw pads of dogs: 24 cases (2000-2007). J Am Vet Med Assoc 2009;234:1555-1558.

Blythe LL, Gannon JR, Craig AM. Care of the racing greyhound: a guide for trainers, breeders, and veterinarians. Santa Barbara, Calif: Veterinary Practice Publishing Co, 1994;185-229.

Borghese IF. Corns and warts: definitions, causes, and treatments. Celebrating Greyhounds 2003;8:48-51.

Freeman DB. Corns and calluses resulting from mechanical hyperkeratosis. Am Fam Physician 2002;65:2277-2280.

Guilliard MJ, Segboer I, Shearer DH. Corns in dogs: signalment, possible aetiology and response to surgical treatment. J Small Anim Pract 2010;51:162-168.

Kapatkin AS, Garcia-Nolen T, Hayashi K. Carpus, metacarpus and digits. In: Tobias KM, Johnston SA, eds. Veterinary surgery: small animal. St. Louis, Mo: Elsevier Saunders, 2012;785-800.

Machery CL, Freeman WE. Using a dental root elevator to remove footpad corns in dogs: two practitioners’ experience. Vet Med 2006;101:778-780.

Swaim SF, Amalsadvala T, Marghitu DB, et al. Pressure reduction effects of subdermal silicone block gel particle implantation: a preliminary study. Wounds 2004;16:299-312.

Swaim SF, Marghitu DB, Rumph PF, et al. Effects of bandage configuration on paw pad pressure in dogs: a preliminary report. J Am Anim Hosp Assoc 2003;39:209-216.