Have you pulled off your boots after a long day of hiking and been startled to find a black toenail? You probably have a case of 'hiker's toe.'
A black or bruised toenail is a common trail souvenir. The discoloration under the nail comes from trauma and bruising to the nail bed. Known as a sublingual hematoma, this malady can happen due to an acute episode of trauma or be the effect of cumulative stress on the area. Usually, this discoloration resolves on its own, although it may take a while. In some cases, the bleeding can be enough to raise the nail from the bed and cause pain. You'll want to consult with your doctor if this happens so that they can drill a few holes in the nail to drain the blood and relieve the pressure. If you feel a characteristic throbbing in the nail due to swelling, that's a sign to seek medical attention.
Will I lose the nail?
The chances are good that if the bruising is significant, the nail will fall off. Don't force it. If it starts to come loose in one area, trim it down so that it doesn't catch on your footwear and let the rest of the nail loosen on its own. Once the nail comes off, the skin underneath may be sensitive. Apply antibiotic ointment and cover the area with a bandage until the skin toughens up. Assuming the nail bed is still healthy, a new nail should begin to grow right away.
Prevention
The most common cause of toenail bruising is ill-fitting shoes. Sure, your shoes might be comfy at the start of the trail, but your foot likely swells after a few miles, and suddenly, the shoe is too small. Trauma occurs when the nail continues to hit the end or top of the shoe. The foot is most vulnerable to this when hiking downhill. Conversely, if the shoe is too big, the foot will slide down toward the toe, and the same mechanism of injury will occur.
Prevention strategies include buying hiking shoes at least a half size bigger than usual. Also, consider your need for a wider size based on how much your feet typically swell. Another strategy is to lace your shoes using a runner's loop or ankle lock to keep your heel well-seated in the back of the shoe. Lastly, keep toenails trimmed so that they don't extend over the toes and hit the inside of the shoe.
When to worry
Fungal infections are another cause of nail discoloration. The colors can range from yellow to purplish. In this instance, you may notice that the discoloration spreads to other toes. Melanoma can also occur in the nail bed under the nail and cause discoloration of the skin. Telltale signs of melanoma include painless changes in color without incidence of trauma and that the discoloration is not limited to the nail. If you notice that it creeps to the cuticle or beyond the nail bed, seek medical attention.
A hiker's feet are their most valuable asset. Taking good care of them is paramount. Keep toenails trimmed and avoid ill-fitting shoes to keep nails healthy on the trail.