A 33-year-old man presents to the emergency department after slamming his finger in the car door 5 hours ago. He initially experienced pain which is currently well controlled with acetaminophen. The patient is otherwise healthy and does not take any medications. His temperature is 98.5°F (36.9°C), blood pressure is 123/79 mmHg, pulse is 90/min, respirations are 11/min, and oxygen saturation is 97% on room air. Physical exam is notable for the finding in Figure A. A radiograph of the affected digits shows a smooth cortex without disruption of the bone. Which of the following is the most appropriate management for this patient?
Fingernail removal
Trephination
Excision and histological examination
Operative repair
Trephination
This patient is presenting after trauma to his finger with a subungual hematoma. Given that he has no other associated injuries, trephination is the only management indicated.

A subungual hematoma occurs after trauma to the finger leading to a collection of blood under the fingernail. Depending on the mechanism, this can be associated with a distal phalanx fracture. Evaluation for a fracture should include a thorough history, exam, and radiography. If there are no other signs of injury including nailbed dislocation or an open fracture, then management requires only trephination (putting a hole in the nail to allow blood to drain) as this alleviates pressure on the nailbed matrix thus preventing possible irreversible damage.

Rsoer et al. compare nail bed repair to nail trephination for subungual hematomas in children. The authors find that there was no difference in complications or outcomes between nail bed repair and trephination; however, the cost in the nail trephination group was lower. The authors recommend nail trephination for children with a subungual hematoma and an intact nail and nail margin.

Figure/Illustration A shows the physical exam finding of a subungual hematoma with a collection of blood underneath the fingernail bed (green circle).

Incorrect Answers:
Answer A: Excision and histological examination could be appropriate management of melanoma, which may present under the fingernails with a hyperpigmented, irregular skin lesion, or a “barcode” appearance if it is at the base of the nail. A spontaneous subungual hematoma could be suggestive of melanoma; however, in the setting of trauma, it is a much less likely diagnosis.

Answer B: Fingernail removal should only be performed if there is also nail avulsion or nail fold disruption to allow for inspection of the nail bed and repair of any laceration. Failure to repair a nailbed laceration could lead to permanent deformity of the fingernail when it regrows.

Answer C: Observation is inappropriate as the accumulation of blood under the nail in a subungual hematoma could lead to ischemia and permanent injury to the nailbed. When a subungual hematoma is present, trephination is indicated.

Answer D: Operative repair may be necessary for fractures; however, this patient has no fracture and only has a subungual hematoma which can be drained easily.

Bullet Summary:
A subungual hematoma is common after trauma, presents with a collection of blood under the fingernail, and should be treated with trephination.