From the Research
For a subungual hematoma in a 5-year-old that occurred 4 days ago and is now separating from the nail fold, the best approach is to allow it to heal naturally without intervention. At this point, no treatment is necessary as the nail is already in the healing process. The most recent and relevant study on this topic is from 2014 1, which discusses the management of simple nail bed lacerations and subungual hematomas in the emergency department, but the key takeaway for this specific scenario is that intervention is not required at this stage. Keep the area clean by washing gently with mild soap and water daily, and cover with a clean adhesive bandage if the child is active or if the nail is catching on things. Apply a small amount of antibiotic ointment like Bacitracin or Neosporin if there's any exposed nail bed. Monitor for signs of infection such as increasing pain, warmth, redness extending beyond the nail, or pus. The damaged nail will eventually fall off completely as the new nail grows underneath, which typically takes 3-6 months in children. This process is normal and painless. Drainage procedures like trephination are only helpful within the first 24-48 hours after injury to relieve pain from pressure, but are unnecessary now since the hematoma is already separating naturally, as supported by the systematic review in 2012 2. It's also worth noting that the outcome in terms of nail cosmesis does not appear to be affected by the mode of treatment, as concluded in the systematic review 2. Therefore, the focus should be on monitoring for complications and supporting the natural healing process.