Black Toenails


Why are my toenails turning black?

The most common cause for black toenails is trauma. Any time the nail is stomped on, dropped on, or banged against something (a soccer ball, a table or chair leg, or even the fronts of your shoes), you risk damage that could result in a subungual hematoma. That’s the medical term for blood from an injury that pools under the nail.

The pooled blood doesn’t stay fresh, but turns darker and thickens. This discolors the nail, but also puts pressure on the tissues around it, because the blood has nowhere to go. The toe can become painful, and foul odor or a discharge can occur.

There are a couple of other instances where your toenail could turn color: a fungal infection that degrades the nail keratin, or malignant melanoma, a dangerous but rare form of cancer. You should always get a medical diagnosis for what’s causing your discolored nails, to rule out other such things, as well as fractures or damage to the nail bed. For an assessment, or for ideas on how to treat black toenails, call Rocky Mountain Foot & Ankle Center in Colorado. You can reach all four of our Denver area offices at (303) 423-2520.

How do I prevent black toenails when running?

As with other aspects of running and injury, preventing black toenails involves your shoes. Since the injury often occurs because they are too tight, use these tests when shopping for running shoes:

  • Toes can lie flat
  • There is a half inch beyond your longest toe
  • They are breathable so your feet don’t stay damp and slide around in them
  • Make sure you can adjust the lacing for downhill running

Socks make a difference, too. They should be absorbent but not hold on to the moisture. What you want is a fabric that pulls the moisture away from your skin and disperses it out through the shoe.

As for your runs—training or racing—it may be best not to do long, high intensity workouts every day. The trauma can accumulate on a long or hard run and end up injuring your nail. Intersperse your high intensity runs with other types of training to let your tissues heal in between.

For more advice on training techniques or shoe choice, contact Rocky Mountain Foot & Ankle Center in the west Denver area. Call (303) 423-2520 for an appointment at our Wheat Ridge, Golden, Evergreen, or Granby location, or request one online.

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