Often, toenails fall off after an injury or trauma, or even after micro trauma, such as repetitive motion after running a race.  An injury such as dropping something on your toe or stubbing your toe or even micro trauma or repetitive trauma such as running many miles or walking in tight shoes can disrupt that growth.  Such trauma can disrupt the soft tissue connections that the nail needs to grown, which include an interruption in blood flow, oxygen, and nutrients. If damage occurs at the nail bed level or under the cuticle, the nail may be permanently affected and will cause the nail to grow back thicker or discolored.  It may also be a precursor for a fungal nail. If you do have a nail injury, make an appointment and have one of our doctors evaluate it for permanent injury, or to determine if there is a fungal infection.  If there is a fungal infection, then we can discuss the treatment options available including topical medications.