The first sign that an ingrown nail is present is pain in the corner of the nail. Swollen, red skin on the painful side of the toe can also indicate an ingrown toenail. Ingrown toenails are caused by tight shoes that crowd the toe area, cutting toenails too short or curved, injury, nail infections, and certain medical conditions.
To prevent ingrown toenails, be sure to maintain good nail hygiene and trim nails straight across, not at a curve. Wear shoes that fit properly and check your feet often, especially if you have a medical condition such as diabetes.