Management of Subungual Hematoma

Management of Subungual Hematomas


Subungual hematomas, sometimes referred to as a fingernail or toenail blister, occur following direct blunt trauma to the digit. Examples of mechanism might include dropping something on your tie, slamming your finger in the car door or stubbing your toe. Subsequently, there is bleeding under the nail and hematoma formation. Most patients will report throbbing toe/finger pain with some form of discoloration of the nail. On exam there will be dark or purple discoloration under the nail with some degree of tenderness. It is important to evaluate for other injuries.

Case Vignette

A 34 year old patient presents to your clinic for toe pain. She states she hit her big toe really hard on the nightstand the previous evening. She states her nail is really painful and the toe is swollen and blue. Which of the following injury patterns would be the best candidate for trephination?

A) Evidence of infection
B) Displaced fracture
C) Extensive nail bed injury
D) Isolated subungual hematoma

Simple hematomas can be defined as occuring in isolation. However, many are associated with other injuries such as nailbed lacerations, fingertip avulsions and fractures. One study of subungual hematomas in fingers found about 1/3 were associated with phalanx fractures and nailbed lacerations.[1]Simon RR, Wolgin M. Subungual hematoma: association with occult laceration requiring repair. Am J Emerg Med. 1987 Jul;5(4):302-4. The presence of other injuries can change management.
Initial management will routinely, but not always involve radiographs depending on mechanism and exam. The vast majority of cases are managed without any surgical intervention. In patients who are asymptomatic or more than 48 hours from presentation, no intervention is typically required. Patients can be treated with NSAIDS and Acetaminophen as needed.


Image 1. Trephination using the heated paperclip technique.

Image 2. Trephination using the needle technique.

Trephination uses electro-cautery or a large gauge needle to fenestrate the nail over the hematoma and decompress the hematoma. Most patients will tolerate this procedure well and have resolution of symptoms immediately following the procedure. In general, indications include duration less than 48 hours (as longer duration hematomas are likely clotted off and will not aspirate out), and the absence of obvious nailbed laceration, fingertip avulsion or open fractures.
The procedure itself is pretty straight forward. Once the decision is made, electrocautery or an 18 gauge needle can be used. A digital block with a local anesthetic is optional but not necessary. Sterile technique should be used before beginning the procedure. To puncture the nail, place your preferred device on the center of the hematoma and apply gentle pressure. Avoid the lanula and matrix. Withdraw as soon as blood is released from the fenestration. Apply gentle pressure to the sides of the nail to help milk blood out of the fenestration.
Video demonstration of trephination using electrocautery.

Additional Considerations

Nail removal is indicated if there is associated nailbed avulsion, complex laceration, fingertip or toe avulsion. However, for most patients this procedure is not necessary. This procedure requires a digital block.
Antibiotics are not indicated in most patients, even those with a tuft fracture. Antibiotics should be given in high risk patients such as diabetics or those who are immunocompromised with any open fracture. In kids, a salter harris fracture is also high risk and requires antibiotics. Tetanus prophylaxis is indicated when appropriate. In athletes with a sport related mechanism, consideration can be made co alter footwear to reduce risk.

After Care & Prognosis

Following trephination, the athlete should keep the toe dry and clean. It can continue to drain for 24-48 hours.  Patients should be counseled to return if there is reaccumulation of the hematoma or evidence of infection.

Patients with an isolated subungual hematoma can return to sport and practice immediately without any specific rehabilitation. Patients with nailbed injuries or fractures will require immobilization and a more delayed return to play.
Overall, about 2/3 of patients report good or excellent outcomes following trephination.[2]Meek S, White M. Subungual haematomas: is simple trephining enough? J Accid Emerg Med. 1998 Jul;15(4):269-71. Historically, hematomas >50% were recommended to have nailbed removal, however recent studies have failed to show a difference in short- or long-term outcomes, including the presence of infection or nail deformity with removal vs trephination.[3]Roser SE, Gellman H, Comparison of nail bed repair versus nail trephination for subungual hematomas in children, J Hand Surg 24(6):11661170, 1999.[4]Seaberg DC, Angelos WJ, Paris PM. Treatment of subungual hematomas with nail trephination: a prospective study. Am J Emerg Med. 1991 May;9(3):209-10. Finally, complications although rare include poor nailbed cosmesis (including deformity or loss), onycholysis (separation of the nail plate from the nail bed), and infection.

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Case Conclusion

Best answer is D. Trephination is the use of cautery, needle or otherwise to decompress a hematoma below the nail. Most patients tolerate this procedure well and have immediate improvement in pain. The literature is not clear on which patients should not receive trephination, however the rest of the choices are not as good of a candidate. Soft contra-indications include displaced fractures, intra-articular fractures, extensive nail bed injuries, infected wounds, and polytrauma. In these patients, you should strongly consider involving orthopedics or podiatry.
Meek S, White M. Subungual haematomas: is simple trephining enough? J Accid Emerg Med. 1998 Jul;15(4):269-71.