Regular runners are probably familiar—either from personal experience or someone they know—with black toenails, a condition marked by a darkened discoloration under the nail. It’s so common among distance runners that many simply accept it as a fact of life, or even view it as a kind of badge of honor.

Don’t think that way! While it’s true that competitive runners will probably deal with black toenails from time to time regardless, many cases are preventable if you’re smart about it—and you want to prevent them if you can, because black toenails can lead to pain, infection, or even serious complications like amputation if they are underestimated and not treated with care.

Here are some things to look out for to limit your risk:

Footwear. By far the most common cause of black toenails is running in shoes that are too cramped or not laced properly. You want plenty of room in the toe box so toes are not pressed against the inside of the shoe, even when a little swollen from extended running. At the same time, the fit should be snug enough to avoid your shoe sliding around, slamming your toes into the front of the shoe.

Nail trimming. Keep nails trimmed short and square from corner to corner—do not curve them.

Terrain. Hilly terrain increases the likelihood of black toenails—particularly downhill running, as it tends to increase vertical impact force. We know that the Piedmont region isn’t exactly known for flat terrain, but it may be helpful to look for flatter stretches of land if you experience repeated problems with toenail bruising.

Moisture. Keeping feet dry over a long run isn’t always easy, but damp feet, socks, and shoes are more likely to slide around as you run, causing the kinds of repeated small collisions that bruise toenails over time. Always opt for breathable shoes and moisture-wicking socks to stay dry.

If you have a black toenail, don’t ignore it—see the experts at Carolina Podiatry Group to limit your risk of complication, especially if discoloration affects more than 25% of your nail, doesn’t improve after a week or so, or you experience feverish symptoms (a telltale symptom of infection). To set an appointment, call us at 888-569-9559.

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