An ingrown toenail can develop when part of a nail pierces the surrounding skin and starts to painfully grow inwards. Ingrown toenails often affect the big toe, though can develop on any of the lesser toes too.They may affect one or both sides of the toenail, on one or both feet.
Once the nail penetrates the skin, the toe becomes vulnerable to complications like infection – especially as the wound can’t heal or close while the nail is piercing it and continues to grow deeper.