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 ...

A black line on your nail (medically known as melanonychia) causes a streak of dark pigmentation that runs along the nail bed. It can be a normal color variation, especially in people with darker ...

Michelle Tagliamonte, 58, was getting a manicure when she noticed the black lines on her thumb, which signaled the start of a fast-spreading cancer.