If you're a runner, you know that black toenails are common—but that doesn't mean you have to put up with them. Beth Skwarecki is Lifehacker’s Senior Health Editor and has been writing about health, ...

Subungual onychomycosis is the most common type of toenail fungus and affects the nail bed and underside of the nail. White superficial onychomycosis causes white spots and flaky patches on the ...