Thick, yellow toenails left so long they split and crumble. Nails so misshapen they dig into the skin, causing infections. Or, in the most severe cases, curling into what we call ‘ram’s horns’ that ...

Onychomycosis is a yellowing of the toenails that often is caused by a fungal infection. Up to 18 percent of the population has this disease at any given time and it tends to get more common with age.

As unsightly as it is, the infection is usually manageable — but only with the right treatment. Here’s how to kick it. Credit...Joyce Lee for The New York Times Supported by By Caroline Hopkins Q: It ...