We’re all guilty of using a small, curved fingernail clipper across the toes (and even the big toe). Whether it’s a routine habit of yours or a one-off solution when you couldn’t find a toenail ...

Question: For the last few years I have noticed the big toenail on my left foot is much thicker than it used to be. It is also slightly yellowed. I am in my 40s. What is this and will it spread to ...