Black Toenails are Common in Distance Running

Over my 30+ years of distance running, I've had many black toenails. In fact, I suffered one at Ironman Texas last weekend! A few of my friends, who also participated, stopped by the office this week for black toenail treatment. The following is my advice in trying to avoid and treat this common problem.

Almost everyone who runs will eventually get a black toenail. Getting your first one is a sign that you are now part of the endurance club. Its kinds like cycling. There are two types of cyclists; those that have fallen and those that will fall. While most runners blame a shoe that is too small, this is often not the main cause. Mine was from the well-meaning volunteers who soaked my running shoes trying to cool off the triathletes with their hose! Squish, squish, squish for 26.2 miles equals blisters and black toenails!

If a toe is under pressure from the shoe or a sock that is too tight or too thick, the sustained pressure, step after step, produces an impact or a friction problem between the toenail and the tissue surrounding it. When the tissue gets damaged, fluid accumulates. This is known as a subungual hematoma. The red or black color is the result of a few blood capillaries that become broken in the process. The more fluid that accumulates, the more pain. The extra fluid, colored by some blood, accumulates below the toenail. When the pressure gets too great, the existing toenail will be separated from the nail bed.

Really, most of the pressure that results in this "toenail injury" is produced by the regular action of the foot coming forward, thousands of times every mile. Each time your foot swings forward, a little extra blood is pushed into the toe region due to the force of the foot coming forward. If you increase your distance regularly and very gradually, your toes will adjust to each new maximum distance and only complain when you extend farther. In a marathon training program, almost everyone gets at least one black toenail. Running faster too soon and too long will increase the chance of this injury.
Hot weather also improves your odds of getting one. When it's warm, your feet swell more than they would on cold days. Because there is more pressure, and more fluid, there are more black nails generated during the summer months. This is especially true when it is humid!

How do I prevent black toenails?

You'll reduce the chance of a black nail if you ensure that you have enough room in your toe area when you fit your shoes. At least half an inch is needed, when you're standing in the prospective shoes (in the sitting position, the toes aren't all the way forward). If you've had a history of black toenails and summer is approaching (or here), you may want more toe room. When you add more room at the end, ensure that the arch of the shoe matches up with your arch. Also, run in the shoe before you buy it to make sure that the shoe isn’t too big and that your foot doesn't slide forward as you're running, which can aggravate the toe more than a tight toe box.

Do all black toenails need to be treated?

Leave black toenails alone and allow them to grow out if they are not painful. About 70 percent of the black toe problems are best treated by ignoring them. The damaged part of the nail is gradually pushed out, and the foot slowly returns to normal. If they are painful, red, or swollen; time to see your podiatrist.

Can I just stick a needle in it to drain it?

Do not attempt bathroom surgery! Many runners will heat up a needle and drain the fluid under their nail. Often this introduces bacteria and now you have a painfully infected toe!
Take any sign of infection seriously. If it continues to hurt or the pain increases, this is a bad sign. Toe infections can lead to cellulitis (blood poisoning), gangrene, and worse, especially if you have diabetes. See your podiatrist first, not last!

Will I lose my toenail?

The short answer is - yes. It will take a few weeks or months, but as the toenail continues to grow, eventually it shoves out the damaged, blackened toenail. The black toenail is raised off of the toenail bed, and underneath it is often the healthy remainder of your toenail. Your black toenail will gradually loosen from the sides and you will be able to trim it away.

When will my toes be pretty again?

If pretty toes are important to you, you can paint the black toenail or even the thin new toenail, or the bare skin. You can also stop by Healthy Steps and have a prosthetic nail put on by our licensed medial nail technician. Most people won't notice the difference if you use a darker shade of polish. Full replacement of your toenail takes about 3 to 6 months, and the new toenail will often be a bit wavy, thin in some areas and thicker in others. After 8 to 10 months your toenail should be back to normal (unless you get a side infection of fungus….another topic).

Black toenails are part of distance running, but take them seriously or they can stop you in your tracks!