Ingrown toenails are a common, painful condition that occurs when skin on the side of a nail grows over the edges of the nail, or when the nail itself grows into the skin. Ingrown Toenail Click on the image to view a larger version.
Ingrown toenails can develop for many reasons.
In some cases the condition is congenital, such as toenails that simply are too large. Persons whose toes curl, either congenitally or from diseases like arthritis, are prone to onychocryptosis. Often, trauma, like stubbing a toe or having a toe stepped on, can cause a piece of the nail to be jammed into the skin. Repeated trauma, such as the pounding to which runners typically subject their feet, also can cause ingrown nails. Ingrown nails also can be caused by incorrect cutting or trimming, causing them to re-grow into the skin, or by excessively tight stockings or shoes with narrow toe boxes.