Corns and calluses are both marked by thick skin that often forms on the feet. Both types of foot problems are progressive, gradually developing over time.
Corns are very small, round patches of thick skin with a hard center area. Normally, the skin around the hard center is red and inflamed. Corns usually develop on the tops and sides of the toes and can be painful to the touch.
This is not true of calluses, which are usually larger than corns but usually not painful. Calluses lack the hard center and usually equally thick throughout. On the feet, calluses normally form on the balls of the feet or the heels.
In addition to noticing the corn or callus itself, you may also see that your skin appears waxy or flaky in the area affected. The feet may become gray or yellow where the callus or corn is located.
Occasionally, corns and calluses may become infected, resulting in redness, pus and a warm feeling to the touch. This type of infection needs to be treated by a doctor and usually requires oral or topical antibiotic medications.