What is the treatment for a contusion (bruise) to a fingernail?

Treatment of Fingernail Contusion (Subungual Hematoma)

For a simple fingernail contusion with subungual hematoma where the nail plate remains intact, drain the hematoma using an 18-gauge needle under local anesthetic block to achieve immediate pain relief—nail removal and exploration are not required. 1, 2

Initial Assessment

Perform a focused examination to determine the extent of injury and guide treatment decisions:

• Check for nail plate integrity: If the nail plate is intact and only a hematoma is present, conservative drainage is sufficient 2
• Assess for associated injuries: Evaluate for distal phalanx fractures, nail bed lacerations, or nail avulsion that would require more extensive intervention 2
• Perform neurovascular examination: Check pulp capillary refill and 2-point discrimination compared to an uninjured digit 2
• Evaluate range of motion: Ensure no tendon or joint involvement 2

Treatment Algorithm

For Intact Nail Plate with Subungual Hematoma

• Administer local anesthetic block before the procedure for pain control 3, 1
• Drain the hematoma using an 18-gauge needle rather than a heated paper clip, which can sear the underlying fluid and plug the hole 1
• No nail removal or nail bed exploration is required when the nail plate is intact 2

For Nail Plate Injury or Avulsion

If the nail plate is damaged or partially avulsed:

• Remove the free-floating proximal portion to prevent it from serving as an irritant or hiding underlying pathology 1
• Perform meticulous cleaning and repair of the nail bed after nail removal 4, 3
• Obtain bacterial cultures if pus is present and initiate antibiotics with coverage against Staphylococcus aureus and gram-positive organisms 4, 3

Adjunctive Care

Immediate Post-Injury Management

• Apply ice therapy in repeated 10-minute intervals rather than continuous application to achieve target temperature reduction of 10-15°C while avoiding skin compromise 5
• Use melting iced water applied through a wet towel for most effective cooling 5
• Note that reflex activity may be impaired for up to 30 minutes following ice treatment, increasing susceptibility to reinjury 5

Ongoing Wound Care (If Nail Removed or Infection Present)

• Apply daily dilute vinegar soaks (50:50 dilution) to nail folds twice daily to reduce inflammation 4, 3
• Use mid to high potency topical steroid ointment to nail folds twice daily for edema and pain 4, 3
• Trim nails regularly until the nail plate grows reattached 4, 3

Monitoring for Complications

• Watch for signs of infection: Increased pain, redness, swelling, or purulent drainage warrant antibiotic initiation 4, 3
• Monitor for chronic onycholysis or persistent subungual hyperkeratosis, which can develop if the nail is not properly managed 4, 3
• Reassess after 2 weeks if infection develops to determine if oral antibiotics and local care are effective 6

Critical Pitfalls to Avoid

• Do not use heated paper clips for drainage as they can sear fluid and plug the drainage hole 1
• Do not routinely remove intact nail plates for simple subungual hematomas—this is unnecessary and increases morbidity 2
• Do not apply continuous ice as repeated 10-minute intervals are more effective and safer 5
• Do not start prophylactic antibiotics for clean injuries without signs of infection 6