dermatologic disorders
Nail Trauma
Subungual hematoma
Subungual hematoma occurs when blood becomes trapped between the nail plate and nail bed, usually as a result of trauma. Subungual hematoma may cause significant and throbbing pain, bluish black discoloration, and, unless small, eventual separation and temporary loss of the nail plate. When the cause is a crush injury, underlying fracture and nail bed or matrix damage may occur. Nail bed or matrix damage may result in permanent nail deformity. If the injury is acute, How To Do Nail Trephination (eg, creating a hole in the nail plate using a cautery device, 18-gauge needle, or red-hot paperclip) can help relieve pain by draining accumulated blood; after 24 hours, blood is coagulated, thus trephination offers no benefit. It is not clear whether removing the nail and repairing any nail bed damage reduces risk of permanent nail deformity. 