From the South Shore Breaker news article:
However, one of the most common, and least discussed, risks to your foot health is onychocryptosis, or as the most of us know it, the ingrown toenail.
In fact, the Institute for Preventive Foot Health estimates that nearly 20 per cent of the population aged 21 and older have experienced an ingrowing toenail at some point in their lives.
An ingrown toenail occurs when the side of the nail cuts into the skin next to the nail. At first mention it sounds pretty harmless; after all, how much damage can a tiny sliver of misdirected toenail really cause?
Read more at the link:
http://thechronicleherald.ca/southshorebreaker/1404736-dangers-of-ingrown-toenails