May 23, 2023/Exercise & Fitness

Damage Control: What To Know About Runner’s Toe

A few precautions can keep your toenails from turning black and falling off

black toenail from running

Shiny marathon medals often symbolize the miles and miles of training logged by hard-core runners. The same can be said for black, loose or missing toenails.


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A condition dubbed “runner’s toe” can be a byproduct of a regular and robust running routine that covers loooong distances. To some, it serves as a badge of honor, representing grit and determination.

But nobody truly considers runner’s toe a reward. It doesn’t look great, after all. Plus, it can hurt.

Luckily, it’s possible to run and keep your toenails looking good if you take a few preventive steps. Let’s take a few laps around the good advice track with podiatrist Georgeanne Botek, DPM.

What causes runner’s toe?

Your toenails can take quite a beating when you’re pounding the pavement or hitting the treadmill, notes Dr. Botek. Every stride may put a bit of stress on your toenails (particularly on your big toe). Over time, that can take a toll.

“Runner’s toe” describes the damage caused by pressure, shearing and friction as your toenail repeatedly and forcefully makes contact with the front or side of your shoe. This repetitive impact can lead to bleeding under your toenail (subungual hematoma).

“The black or dark color you see under your toenail may be bruising or blood,” explains Dr. Botek.


Symptoms of runner’s toe

Aside from the cosmetic issue of a discolored toenail, runner’s toe also may lead to:

  • A feeling of pressure. Blood building up in the confined space beneath a toenail can push against the toenail, leading to definite discomfort and tenderness.
  • Blood blisters. A pocket of blood may form behind the nail and force it up. This can be painful and may lead to an infection. It’s best to talk to a healthcare provider if runner’s toe pain lingers or increases. Draining the blister may be an option.
  • Loss of a toenail. It’s possible your nail loosens or even falls off due to the damage done. Resist the temptation to pull a loose nail. “That can cause the nail bed to tear and scar,” warns Dr. Botek. “Then, you’ll have a deformed nail as the new nail grows in.”
  • Toenail damage. Thickening, callusing and disfiguring of your toenail.
  • Ingrown toenail. Toe trauma or poorly fitting shoes can cause an ingrown toenail, with the resulting pressure along the skin edge leading to pain, callusing and even infection.

Runner’s toe treatment

Easing up on activity, especially if you’re experiencing pain, will give your toenail a chance to heal. The blackened toenail will eventually grow out over time. (The process may take months, as toenails grow much slower than fingernails.)

It’s also a good idea to get your feet properly sized at a local shoe store to assure you have enough toe box space in your shoes. This can help limit the friction that causes runner’s toe.

Try to avoid painting over black toenails with polish, recommends Dr. Botek. While it may improve the appearance of your toenail, polish also prevents your nail from breathing and isn’t healthy for long periods of time.

It’s also possible that a damaged toenail may have to be removed by a podiatrist. It can take months for a new nail to grow back in.

And as mentioned earlier, draining pooled blood from behind a toenail also may provide relief.


Other causes of black toenails

Sweaty running shoes offer the perfect environment for a fungal infection, which can thicken a toenail and turn it black. A growing number of medications — topical and oral over-the-counter and prescription medications — are available to treat mycotic nails.

In rare cases, a black spot under the nail can be a melanoma, or skin cancer. See a doctor if you have a dark spot under your nail that doesn’t go away.

Is runner’s toe just for runners?

Don’t be fooled by the name, says Dr. Botek — runner’s toe has a much broader reach and can be a source of frustration for:

  • Soccer players (with damage to the nail often done by kicking the ball).
  • Tennis, pickleball, racquetball or squash players.
  • Rock climbers.
  • Dancers.

How to prevent runner’s toe

While runner’s toe can happen to runners, it doesn’t HAVE TO happen, says Dr. Botek. Following these six tips may keep your nails healthy and intact:

  1. Try silicone toe pads. A little extra padding can help absorb some of the pavement-pounding pressure that comes running, offering just enough cushion to keep your toenails happy.
  2. Find a running shoe that fits. When buying running shoes, a good rule of thumb is to give your toes some space — but not so much that your foot slides around. Get regularly fit for shoes, too, as your foot size may change over time.
  3. Keep your toenails cut short. The less your toenail extends out, the less likely it will hit the top or sides of your shoe when running. (Be sure to cut your nails correctly to avoid ingrown toenails, too.)
  4. Adjust your shoe laces. If your foot is sliding a bit in your shoe, retying your laces may help you get a better fit that keeps your foot in place and protects your toes.
  5. Wear moisture-wicking socks. Drier socks can keep your feet from slipping around inside your shoe and reduce shearing and friction. Plus, less moisture near your toes is a good thing.
  6. Consider the terrain. Running downhill naturally pushes your toes forward in your shoes. Finding flatter ground for some runs can limit the damage inflicted on your toenails.

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