If you’re a consistent runner (or recently upped your mileage), black, loose or missing toenails may be as much a part of the sport as race t-shirts and post-run bananas.
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Sometimes, your first black toenail is even considered a badge of honor in the running world! But what causes the toenail to turn black in the first place and can you prevent it?
Why running can turn your toenails black
Your toenails can take quite a beating as you’re pounding the pavement, says Dr. Botek. Damage occurs when your toenail repeatedly and forcefully makes contact with the front or side of your shoe. Basically, the black or dark color your see under your toenail is just bruising or blood.
Usually black toenails aren’t very painful, but sometimes the trauma of your toes hitting your shoe can create pressure, which can lead to pain.
Blood blisters can also develop under the toenail secondary to the trauma and friction. The action can lift up the toenail, which may cause the nail to eventually fall off.
Black, loose or missing toenails can be a common injury among runners, especially those who are training for marathons or highly competitive runners training at high intensity.
Your toenails will heal when you ease up on your training and the repetitive trauma (aka your running mechanics) ends or changes.
Blood blister basics
Blood blisters that lift the nail plate up are often painful and an infection can develop if left untreated. It’s important to consult your doctor or podiatrist if you’re having continued or increasing pain or something doesn’t look or feel right with your toenail.
When the nail lifts, it’s tempting to pull off the entire nail. But don’t, warns Dr. Botek.
“Whatever you do, don’t pull off the nail yourself as that can cause the nail bed to tear and scar,” she says. “Then you’ll have a deformed nail as the new nail grows in.”
If too much blood collects under the nail, it may be necessary to have a podiatrist drain the blood, which can give you some relief from the pain.
Some runners try to hide their black toenails with polish, but avoid the paint, Dr. Botek says. While polish can improve the appearance of your toenail, it also prevents the nail from breathing and isn’t healthy for long periods of time.
Other causes of black toenails
Another cause of black-looking toenails is fungal infection, which can thicken the nail and sometimes turn it very dark. A fungal infection can be treated with medications topically or orally. A growing number of medications — over-the-counter and prescription — are available.
In very rare cases, a black spot under the nail can be a melanoma, or skin cancer. If you have a dark spot under the nail that does not go away, see your doctor.
Here’s how to reduce your chances of getting a black toenail
Dr. Botek shares 5 tips to help protect your toenails when running:
- Try silicone toe pads. They may help absorb some of the pressure from running.
- Find a running shoe that fits. When shopping for running shoes, visit a store that specializes in the sport to get a professional fitting. A good rule of thumb when buying running shoes is to make sure you have enough room in the toes, but not so much that your foot slides around in the shoe. Make sure your toes are not pinched at the top and consider how your socks fit with the shoe.
- Keep your toenails cut short. The less your toenail extends out, the less likely it will hit the top or side of your shoe when running. Be sure to cut your nails correctly to avoid ingrown toenails.
- Tie your laces properly. Adjusting the laces may help you get a better fit.
- Wear good socks. Preventing moisture whether it be from sweaty feet or the weather, socks matter and will reduce the shearing and friction and prevent the moisture that can damage your skin and nails.