What is the next best step in managing a subungual hematoma with a new nail growing beneath, after a finger injury?

Management of Subungual Hematoma with New Nail Growth

The next best step in management for this subungual hematoma with new nail growth is to allow the natural separation and growth of the new nail while keeping the area clean and protected.

Assessment of the Current Situation

The patient presents with:

• Blood blister beneath the nail (subungual hematoma)
• Injury occurred one week ago from pinching while sharpening a lawnmower blade
• New nail growth visible beneath the blood blister
• Current self-care includes triple antibiotic ointment and saltwater soaks
• No signs of infection mentioned

Management Algorithm

1. Allow Natural Separation

   • Since a new nail is already growing beneath the hematoma, forced removal of the old nail is unnecessary and could cause additional trauma
   • The old nail is already separating from the nail bed naturally as the new nail grows

2. Wound Care Instructions

   • Continue to keep the area clean and dry
   • Discontinue saltwater soaks as prolonged soaking can macerate the tissue and potentially increase risk of infection 1
   • Apply topical antiseptic solution (such as povidone-iodine 2%) twice daily instead

3. Protective Measures

   • Cover with a clean, dry bandage when performing activities that might cause trauma
   • Wear protective gloves during manual work to prevent additional injury
   • Avoid manipulation of the nail plate or cuticles 1

4. Monitoring

   • Watch for signs of infection (increasing pain, redness extending beyond the nail fold, purulent discharge)
   • If infection develops, obtain bacterial cultures and consider appropriate oral antibiotics with Staphylococcus aureus coverage 1

Rationale for Conservative Management

When a subungual hematoma is one week old and a new nail is already growing, trephination (drilling a hole in the nail) is no longer indicated. Trephination is most beneficial when performed within the first 48 hours after injury to relieve acute pain from pressure 2, 3. At this stage, the hematoma has likely already begun to organize and the pressure has equalized.

The ESMO guidelines for nail management indicate that once onycholysis (separation of the nail from the nail bed) develops naturally, intervention should be minimal unless there are signs of infection or severe pain 1. Since the patient's injury is already progressing toward natural resolution with new nail growth, conservative management is appropriate.

Potential Pitfalls to Avoid

1. Unnecessary Nail Avulsion: Removing the old nail when a new one is already growing can cause trauma to the new nail and nail bed, potentially leading to permanent nail deformity.

2. Prolonged Soaking: While the patient has been soaking in saltwater, prolonged soaking can actually macerate the periungual tissue and increase infection risk 1.

3. Premature Return to Activities: Advise the patient to protect the finger during activities that could cause additional trauma until the new nail has fully grown in.

4. Missing an Underlying Infection: Although not mentioned in this case, always assess for signs of infection that would require more aggressive intervention.

By following this approach, the patient should experience complete resolution as the new nail grows out fully over the next 3-4 months, which is the average time for complete nail regrowth 3.