What is the best course of treatment for a patient with pressure and bruising to the bottom of the nailbed after slamming it in a car door, considering potential underlying health conditions such as diabetes or bleeding disorders?

Management of Subungual Hematoma from Crush Injury

For a patient with pressure and bruising to the nailbed after a crush injury (car door), perform immediate trephination (nail decompression) if the hematoma occupies >25-50% of the nail surface and the injury occurred within 24-48 hours, as this provides rapid pain relief and prevents nail loss. 1

Immediate Assessment

Evaluate for fracture and compartment syndrome:

• Palpate the distal phalanx for point tenderness suggesting tuft fracture
• Check capillary refill in the affected digit (should be <2 seconds)
• Assess for progressive swelling, severe pain out of proportion to injury, or numbness indicating compartment syndrome 2
• Document neurovascular status including two-point discrimination and motor function 2

Screen for bleeding risk factors:

• Ask specifically about anticoagulant use (warfarin, DOACs, aspirin) 3
• Inquire about diabetes mellitus, as this increases bleeding complications 2-fold even with minor trauma 3
• Check for history of bleeding disorders or easy bruising 4

Treatment Algorithm

If Hematoma >25-50% of Nail Surface AND <48 Hours Old:

Perform trephination immediately:

• Use a heated paperclip, electrocautery device, or 18-gauge needle to create a hole through the nail plate 1
• Apply gentle pressure to express the hematoma
• This provides immediate pain relief and preserves the nail 1

Post-procedure care:

• Apply a simple protective dressing (non-adherent gauze) 2
• Elevate the hand above heart level for 24-48 hours to reduce throbbing 1
• Prescribe ibuprofen 400-600mg every 6-8 hours for pain and anti-inflammatory effect 5

If Hematoma <25% of Nail Surface OR >48 Hours Old:

Conservative management:

• Leave the nail intact and monitor for signs of infection 6
• Apply a protective splint if there is associated tuft fracture 2
• Instruct the patient to keep the area clean and dry 2

Critical Pitfalls to Avoid

Do NOT apply ice directly to the injured digit:

• Ice impairs coagulation and can paradoxically increase bleeding in the nailbed 4
• Cooling prolongs bleeding time and worsens outcomes in hemorrhagic injuries 4
• If pain control is needed, use oral analgesics instead 5

Do NOT remove the nail unless:

• There is a large nail avulsion (>50% detached) 6
• Signs of infection develop (erythema, warmth, purulent drainage) 2
• The nail is completely loose and acting as a foreign body 6

Special Considerations for High-Risk Patients

In diabetic patients:

• Examine carefully for any breaks in the skin, as these can rapidly progress to infection 2
• Ensure tetanus prophylaxis is current 2
• Schedule follow-up within 3-5 days rather than waiting for routine healing 6
• Warn about increased bleeding risk if on anticoagulation (2-fold higher) 3

In patients on anticoagulation:

• Trephination is still safe and recommended for symptomatic relief 3
• Apply prolonged direct pressure (10-15 minutes) after the procedure 2
• Monitor closely for reaccumulation of hematoma 2

Follow-Up Instructions

Instruct the patient to return immediately if:

• Fever develops (>38°C/100.4°F) 2
• Redness spreads beyond the immediate nail area 2
• Pus drains from under the nail 2
• Pain worsens significantly after initial improvement 6

Expected healing timeline:

• Pain should improve within 24-48 hours after trephination 1
• The nail may eventually fall off (normal process taking 2-4 months) 6
• A new nail will grow underneath if the nail matrix remains intact 6