What Is an Ingrown Nail?

Ingrown nails -- when the nail grows into the flesh instead of over it -- usually affect the toenails, particularly the big toe. People with curved or thick nails are most susceptible, although anyone can suffer from ingrown nails as a result of an injury, poorly fitting shoes, or improper grooming of the feet. People with diabetes, vascular problems, or numbness in the toes need to be aggressive in treating and preventing ingrown toenails because they can lead to serious complications, including the risk of losing a limb.

A damaged or improperly trimmed nail can become ingrown, burrowing into the skin at the side of the nail. The site can become painful and infected, and may not heal until the nail is removed. To avoid ingrown nails, always trim nails straight across.

What Causes Ingrown Nails?

Ingrown nails are most frequently caused by cutting your toenails too short or rounding the nail edges or by wearing ill-fitting shoes or tight hosiery that press the nail into your toe. You can also develop an ingrown nail after an injury, such as stubbing or jamming your toe.

If the condition causing the ingrown toenail continues, overgrowth of the tissue over the nail can lead to permanent changes in the tissue that can cause infection, more pain, and more swelling.