DEAR DOCTOR K:
I have a patch of hard skin on my foot. Is it a corn or a callus? How should I treat it?
I can’t answer your question without seeing it. But I can tell you what to look for, and when it requires a visit to your doctor.
Corns and calluses are areas of hardened skin. They develop to protect the foot from the damage that can be caused by friction from poorly fitting shoes. Over time, if the irritation continues, a corn or callus may grow and cause discomfort and pain that interferes with walking.
One big difference between a corn and a callus is location. Calluses usually form on the bottom of the feet. Corns form on top, usually around the toes. Calluses generally consist of a broad area of thickened skin. Corns are smaller and may have a dense knot of skin in the center. Here is an illustration of corns and calluses:
In many cases, better-fitting shoes will reduce the irritation that caused the problem. And most pharmacies sell products that help cushion corns and calluses. Thus protected, the corns or calluses will shrink on their own, over weeks or months.
If you can’t wait that long, you can treat the problem more aggressively. Try a pumice stone to gently remove the top layers of skin. First soak your feet in warm water to soften the skin. Dry your feet, then rub the pumice stone gently over the corn or callus. Afterward, moisturize the area.
Pharmacies sell various chemical peels and acid disks for corns and calluses. But use such products with caution. Most of them contain salicylic acid, which can damage healthy skin.
For larger corns and calluses, a foot-care specialist may have to shave away some of the thickened skin. In some instances, you may need surgery to correct an underlying problem if the irritation is caused by a problem with your foot’s bone structure. Perhaps the most common example is a bunion, a swelling at the base of the big toe.
To prevent recurrent calluses and corns, wear shoes that fit comfortably, provide cushioning in the sole and leave enough room at the toes.
If you have diabetes, peripheral neuropathy or some other circulatory problem, don’t treat the corn or callus yourself. See a foot-care specialist.
I remember a 70-year-old patient who had heart failure, kidney failure and chronic lung disease. Strong medicines were just barely keeping these problems in check. I saw her every three to four months, and at each visit, I asked her lots of questions and performed a physical examination — trying to assure both her and myself that the treatment was working.
She always seemed uninterested in the state of her heart, kidneys and lungs. All she wanted to talk about were her feet — her corns and calluses. When I interrupted her to ask more questions about her various life-threatening conditions, she admonished me: “Doctor, we all have to die of something. But we don’t have to have sore feet.”