A subungual hematoma is found under a nail, or toe nail, and constitutes an accumulation of blood caused by trauma. These nail afflictions are particularly painful, turning the nail red, then blue, then black once the blood congeals. The nail continues to grow normally or drops off, with a new nail growing in its place. If the trauma is recent and the pain
too severe, the blood can be drained from under the nail in order to eliminate the hematoma.