A black line on your nail (medically known as melanonychia) causes a streak of dark pigmentation that runs along the nail bed ...

In about two-thirds of people with nail melanoma, the main symptom is longitudinal melanonychia, a dark vertical streak or line under the nail plate. It may be thin or thick, and light brown to black.

From everyday fungal issues to surprising health warnings, discover what the color changes in your toenails might be trying to tell you about your wellbeing.

Kelly Heather, 38, ended up needing brain surgery for a tumor — and it started as a discolored line on her fingernail Kelly Heather / SWNS (2) Kelly Heather, 38, first noticed a dark line on her ...

They show up as small dark marks under your nail plates and run in the same direction the nail grows. These reddish-brown streaks are 1-3 millimeters long and do not fade or blanch when you press ...