Ingrown toenails are a common problem particularly among teenagers.
They occur when the end or side of the nail begins to grow into the skin of the toe. This growth causes swelling at the site where the nail is intruding in the skin. Infection may start shortly thereafter due bacteria that live on the feet invading the site. Swelling and redness may be present where the nail meets the edge or end of the toe. This part of the toe is usually exquisitely painful.