Black toenail is a problem which is mostly common in athletes. When you walk or run, your foot glides forward in your shoes because of which your toes bang up against the top, front and sides with each step in your shoe. Your feet swell during a walk or run and get compressed by your shoes. This constant pressure and impact damages the toenail bed and create a blister underneath the toenail.
Since your feet can’t breathe inside the shoe, the blister will take longer to heal. Because of this the extra blood and fluid causes the toenail to separate from the toenail bed. Hence the blood colours the toenail black. The toenail first turns black and then the nail falls off usually when a new nail grows in.
The blister underneath the toenail bed causes the toenail to rise and swell. It causes a lot of pain in the toe. Athletes who do lot of running are the most likely candidates for black toenails as their toes are constantly rubbing against the front of their shoes. There are more chances of getting black toes in warm weathers as the feet swell more when it is hot.
If you have a black toenail it is best to leave it alone as long as you can manage the pain. The pain is mostly worst on the first day but will lessen each day after. The damaged nail will gradually push off and a new nail will eventually grow in. The damaged nail will fall on its own, so don’t force the old nail off as it will worsen the pain. It will take a few weeks or months to regain its original shape. If it is still raised or painful after a day, drain the fluid with a sterilized needle and apply antibiotic cream or alcohol. If the toe continues to be red and swollen, consult your doctor immediately to ensure it has not become infected. Take infection seriously as it can lead to blood infection or gangrene. It can be worse if you are diabetes patient.
To avoid black toenails, you must wear the correct running shoe size. It is advisable to wear shoes that are at least ½ inch size bigger than your street size so that there is plenty of room in the toe box for the feet to breathe.
Trim your toenails at regular intervals and keep your feet dry and clean for as long as possible during long runs. Wear good wicking socks rather than the cotton ones. Lace your shoes tighter if you are doing more of downhill running to avoid constant friction with the front of the shoe to avoid black toenail.