Black toenails is something we see with many high performance athletes, hikers, tennis players, cleated athletes and the occasional drop of a heavy object.
Trauma is the most common cause of black toenails and can be the result of the toe being brushed up against a firm object while walking barefoot, it being injured by a heavy falling object or pressed against the wall of a shoe. A tight or restrictive shoe may also cause the nails to press against each other, which over a prolonged period of time (such as the duration of a marathon or a long hike) may cause blood to pool under the nail (in medical circles commonly referred to as subungual hematoma).
Treatment & Prevention
When the trauma is footwear related, ensuring that the toes have ample space in the shoe’s toe box is of utmost importance. We usually recommend a finger width of space between the end of the longest toe and the front of the shoe. Keep in mind that the longest toe may not necessarily be your big toe. To ensure you have ample width in the shoe, run your fingers across the ball of your foot and check to make sure that there is some give in the material and the forefoot isn’t filling out the entire footwear. If you can pinch the material as your fingers meet in the centre the shoes are too wide and you may want to look for a more narrow fitting style. If there isn’t any give, look for something wider.
Improve spacing of your toes with socks such as Injinji. This will help prevent toes from getting squeezed together, although it’s not a substitute for a more spacious toe box.
Reduce pressure on your toes with digital toe caps, or toe condoms, as we like to refer to them. These devices are lined with a gel polymer and wrapped in a nylon (to prevent the item from sticking to the walls of your socks or shoes). This cushions the nail from impact.
Certain brands such as New Balance and Treksta offer roomier toe boxes by design (see Nestfit technology for more information). New Balance also offers a wide range of widths to better accommodate the toes.
Know of any other tips and tricks to help prevent & treat black toenails? Comment below.