Learn about toenail fungus types, symptoms, and prevention methods. Discover what nail changes reveal about your health and immune system.

Medically reviewed by Katlein Franca, MD Toenail fungus, or onychomycosis, is a nail infection that can make your toenails thicker, change color, or break apart. It affects about one in 10 people and ...

From trauma to a toenail fungus, there are many reasons why you may have a black toenail. Here's what it means, how to treat ...