Anatomy:The nail is attached to the outermost part of the toe for protection.
Cause: Bleeding under the toe nail (especially the big toe or the toe adjacent) most often occurs due to the toe repeatedly jolting against the inside of the shoe, or by the athlete having his toes trodden on. Injuries to the toe and nail are extremely frequent in sport (article). Due to the toe nail being so firmly attached to the toe, even small drops of blood collecting under the nail will cause significant pain. The bleeding can loosen the nail, resulting in the nail finally being shed (Photo).
Symptoms: Pain and dark discolouring of toe nail ("Black Toe", "Tennis Toe").
Examination: Medical examination is normally not necessary in cases of bleeding under the nail.
Treatment: The pain normally goes away after a few days' resting of the toe. In cases of acute pain and discolouring under the nail, a hole can be bored in the nail to release the trapped blood and therefore reduce the pain considerably (article). If this course of treatment is followed it is recommendable to soak the foot in soap water several times a day to diminish the risk of infection under the nail. Pain can be treated with ordinary pain-killers (paracetamol), and in some cases supplemented by rheumatic medicine (NSAID). There is only minimal risk of making the injury worse by continuing sports activity, however, if the cause of the injury is due to footwear, the necessary actions should be taken to avoid repeat. The nail can be remove if loose.
Bandage: If the toe nail is loose the pain can be reduced by taping the nail to the toe (tape-instruction).
Complications: In some cases the toe nail is shed, and it can take several months for a new to grow. If there are repeated cases of bleeding under the same toe nail, an x-ray examination should be performed to ascertain whether new bone has been formed (exostose) on the toe bone under the nail ("basketball toe"). In such cases, the exostose can be surgically removed.