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Black Toenail


Updated May 16, 2014

Black Toenail

Black Toenail

© anayah / Depositphotos.com

At the end of a long walk or run, you may notice that a toenail has turned black or gray, and may be swollen under the nail. What happened? What's going to happen?

What is Black Toenail?

As you walk or run, your foot slides forward in your shoe, banging your toes against the top, front, and sides with each step. Your feet also swell during a walk or run and get compressed by your socks and shoes. That pressure and impact can damage your toenail beds, or create a blister under the toenail itself. When this happens, the extra blood and fluid cause your toenail to separate from the toenail bed, or the "toenail in training" as the Jeff Galloway site calls it. The blood colors the toenail black.
Photos of Black Toenail

Is Your Black Toenail Painful?

If there is a blister under the toenail, you may see the toenail raised and it may be swollen and painful. It is best to try to ignore this for 24 hours and see if it goes down by itself. If it is still raised and painful after a day, then you may want to drain the fluid. If the edge of the swollen area is near the edge of the nail, sterilize a needle, sanitize the area, and try to pierce the blister with the needle. Press to drain it, apply alcohol and/or antibiotic cream.

If the swollen area isn't near the edge of the nail, you will need to drill through the nail to drain it. Sterilize a paper clip with a flame, sanitize the nail with alcohol, and while the paper clip is still glowing red, pierce straight down through the nail to make a puncture to drain the excess fluid. Press to drain the fluid. Sanitize the area with alcohol and antibiotic cream.

If the toe continues to be swollen and red after you have drained the excess fluid, see a doctor to ensure it has not become infected. Take infection seriously, if it continues to hurt or the pain increases, this is a bad sign. Toe infections can lead to blood infections, gangrene, and worse, especially if you have diabetes.

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. Most people won't notice the difference if you use a darker shade of polish. Full replacement of your toenail takes about 3 months, and the new toenail will often be a bit wavy, thin in some areas and thicker in others. After 4-5 months your toenail should be back to normal.

How Can I Prevent Black Toenail?

Your running or walking shoes and socks must fit correctly. Your feet swell a full shoe size over the course of a longer run or walk, and your toes must have someplace to expand into. The toebox must be wide enough, yet not too wide or your toes will bang around in it. Getting fit at a technical running shoe store in your area is your best method of ensuring your shoes fit correctly.
Getting Shoes Fit Right

The trauma of toes banging into the shoe can be eliminated by proper lacing of your shoes to keep your heel in the heelbox rather than letting the foot slide forward in the shoe with each step.
See: Shoe Lacing to Prevent Heel Slippage

Reference: Fixing Your Feet: Prevention and Treatments for Athletes by John Vonhof, Wilderness Press, 2006

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