Why is my toenail turning black?

You can develop a black toenail for several different reasons. The most common culprit is trauma. This could be small, repetitive bumps to the ends of the toes over time—like hitting the insides of your shoes over and over again while running. It could also be the result of suddenly stubbing your toe or dropping something heavy on it. In either case, the trauma causes an injury in the nail bed, which leaks blood. This stains the underside of the keratin, causing that dark color.

Occasionally a black toenail is caused by something else. It might be a side-effect of a fungal infection, particularly if there’s a buildup of debris under the nail. A large dark patch, or a dark streak instead of a splotch, may actually be signs of cancer. Malignant melanoma, the most deadly of skin cancers, can sometimes grow underneath a toenail and make it appear black. If the dark splotch doesn’t seem to be growing out with your hard keratin, have it checked right away. Contact Dr. Victoria Melhuish at Sierra Foot & Ankle in Carson City or Gardnerville, NV, to discover what caused your nail problem. Call (775) 783-8037 to make an appointment.