Melanonychia, also known as a dark or black line on the nail, causes a streak of dark pigmentation that runs along the nail ...

Black or brown lines appearing on fingernails or toenails are a common finding and are often dismissed as cosmetic changes (1 Trusted Source Melanonychia: Etiology, Diagnosis, and Treatment Go to ...

Melanonychia is a brown or black stain in your fingernail or toenail. You can have a dark line on one nail, a few nails, or all of your nails. The line is caused by the natural color in your body ...

Your nails serve as more than just a canvas for your favorite polish color. These small but significant parts of your body can reveal important information about your overall health, often acting as ...