A subungual hematoma
is a collection of blood
) underneath a toenail
It often results from a traumatic injury such as slamming a finger
in a door. A laceration
of the nail bed
causes bleeding into the constricted area underneath the hard nail plate. Because the blood disrupts the connections between the nail bed and nail plate, throbbing pain is common. The nail develops a black discoloration overlying the laceration.
Subungual hematomas are treated by either releasing the pressure by drilling a hole through the nail into the hematoma (trephining
) or by removing the entire nail. Trephining is generally accomplished by using a heated instrument to pass through the nail into the blood clot. Removal of the nail is typically done when the nail itself is disrupted, a large laceration requiring suturing
is suspected, or there is a fracture
of the tip of the finger. Although anesthesia
is generally not required, a digital nerve block
may be performed if the nail is to be removed. Subungual hematomas typically heal without incident, though infection
or disruption of the nail (onycholysis
) may occur.