A subungual hematoma is a collection of blood underneath the nail, usually occurring secondary to distal digit trauma. Patients often present with throbbing pain secondary to pressure beneath the nail. Associated injuries include nail bed trauma and distal tuft fractures. When fractures are present, these are considered open.
Management and Disposition
A radiograph should be done to evaluate for fracture. Acutely, if the subungual hematoma involves less than 50% of the nail matrix, trephining the nail with a sterile needle or electrocautery is adequate to relieve pain by allowing drainage. A digital block may be required prior to trephination. The involved digit can be soaked in sterile water with peroxide after trephination to encourage drainage.
Management of larger hematomas is controversial. Some authors advocate nail removal for bed injury repair if the hematoma covers more than 50% of the nail or if there is an associated fracture. Some believe nail removal is best reserved for injuries damaging the nail plate and surrounding tissues, regardless of the size of the hematoma or presence of fracture. After removal, the patient’s clean nail, a piece of foil, or petroleum gauze should be placed between the eponychial nail fold and the germinal matrix.
Subungual Hematoma. Two subungual hematomas secondary to crush injury. (Photo contributor: R. Jason Thurman, MD.)
The patient with a fracture should be discharged with a splint supporting the distal joint in extension, and all dressings should be kept dry. Antibiotics are not required unless the area is contaminated.
Subungual hematomas are a sign of nail bed injury.
Subungual hematomas with surrounding nail bed and nail fold injuries require nail removal and evaluation of the bed for injury and careful repair if needed.
A hand-held, high-temperature, portable cautery device is a good tool for trephination (see video).
Trephination. The hot paper clip formed a nice hole in the nail plate, and the blood drained out spontaneously. This relieved the pressure and gave the patient immediate pain relief. (Photo contributor: Richard P. Usatine, MD. Reproduced from Usatine RP, Smith MA, Mayeaux EJ Jr, Chumley H. The Color Atlas and Synopsis of Family Medicine. 3rd ed. New York, NY: McGraw Hill; 2019.)
Nail Bed Laceration. Bleeding from a nail bed laceration causes a subungual hematoma. This image depicts a nail bed laceration seen after nail removal. (Photo contributor: Alan B. Storrow, MD.)
Video 11-04: Subungual Hematoma Trephination