At first glance, it looks like a wart—but upon closer inspection, a glassy, hard core in the center becomes noticeable: a typical sign of a corn. This small, often painful callus forms where the skin ...

Q: I run a lot and developed a growth on the knuckle of my second toe. It’s hard, with a sharp point in the middle, and it hurts. I thought it was a callus, but my running coach says it’s a corn. I ...