Corns, or footpad keratoses, are hard and painful keratotic growths on the digital, metacarpal, or metatarsal footpads of
dogs, predominantly greyhounds—both active racing and retired (Figures 1 & 2). Little information about corns is available in the veterinary literature.
1. A corn on a digital footpad of a retired racing greyhound.
The cause of corns is unknown, but the most popular theory is that the absence of a thick adipose layer in the greyhound footpad
allows concussive force between the phalanx and footpad, which damages the skin and footpad.1,2 Another theory is that corns result from footpad cuts or punctures that heal and become fibrous and scarred.1,2 Other theories are that a foreign body or a papillomavirus causes corns to form.1,2
Corns can usually be diagnosed during a physical examination. In our experience, a dog with true corns typically will be in
enough pain that it will be limping. Since the cause of corns is unknown, a radiographic examination of the affected paw should
be performed in dogs suspected of having corns to rule out a radiopaque foreign body.
After surgical excision of a corn, a histologic examination should be performed to characterize the microscopic appearance
of the lesion, which is usually described as orthokeratotic hyperkeratosis. Use the histologic examination results in combination with antipapillomavirus immunohistochemistry and papillomavirus polymerase
chain reaction test results to exclude a papillomavirus as the etiologic agent. In addition, the results of a histologic examination
may rule out viral causes of corn formation.
2. A cross-sectional incision on the digital footpad of a retired racing greyhound. Note how deep into the footpad the corn
The treatment method for corns is as debatable as their etiology. Many techniques have been described. All of these treatment
options have varying degrees of success.
Soaking paws and applying manual pressure
We have no experience with soaking the paw and applying manual pressure to express a corn.3 Corns are generally painful with aggressive palpation, and this technique may be more painful and time-consuming than the
core removal technique we describe (see "Dental root elevator technique").
Various surgical techniques have been described, including corn removal with a laser, scalpel blade, or biopsy punch.3,4 However, a high percentage of corns will return two or three months after surgery.1
Amputating the affected digits is another surgical approach to treating corns. However, even after this radical treatment
approach, the risk of corn growth persists in the other digits. It is our opinion that amputation should be performed only
when all other treatment modalities have failed.
Recently, researchers at Auburn University's College of Veterinary Medicine have preliminarily studied whether silicone block
gel particles injected subdermally under the distal interphalangeal joint may help provide increased cushioning similar to
the fibroadipose tissue of the digit and, thus, prevent the recurrence of corns.1
In this study, some migration of the gel occurred, and some gel remained under the pressure point with evidence of fibrous
connective tissue growth around individual gel particles to hold them in place.1 Contact pressure analysis showed a decrease in pressure three months after injection when compared with controls and preinjected