This article summarizes current pediatric and specialty guidance. Every child’s age, history, injury, and procedure are different. Seek urgent in-person care for red-flag symptoms rather than relying on an online article.
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Immediate first aid
Remove rings or tight items before swelling increases. Apply direct pressure with clean gauze for bleeding, elevate the hand, and use a wrapped cold pack for 10 to 15 minutes at a time. Weight-appropriate pain relief may be used according to medical advice.
Do not drill, burn, or puncture the nail at home, and do not pull off a lifted nail. Home drainage can cause burns, infection, or further nail-bed injury and may miss an associated fracture.
Why the nail turns black
A crush injury can rupture small vessels under the nail, producing a subungual hematoma. Pressure beneath the rigid nail may cause throbbing pain. Treatment depends not only on the percentage of the nail involved, but also on pain, nail position, nail-edge integrity, nail-bed injury, and fracture pattern.
If the nail margins are intact and there is no displaced fracture, observation may be enough. A clinician may drain a painful hematoma through a small opening after assessment. Not every dark nail needs drainage.
When an X-ray is needed
Fingertip crush injuries frequently involve the distal phalanx. X-ray is more likely when there is significant swelling or tenderness, refusal to use the finger, deformity, nail-root displacement, an open wound, or persistent pain.
A Seymour fracture is a growth-plate fracture near the fingertip that may be associated with a nail-bed wound. It can behave like an open fracture and requires prompt recognition to reduce infection, osteomyelitis, nail deformity, and growth complications.
When the nail may need removal and nail-bed repair
A split or displaced nail plate, a nail edge pulled out from under the skin, a deep nail-bed laceration, contamination, or an unstable fracture may require anesthesia, irrigation, nail removal, and fine repair of the nail bed.
The purpose is to see and align the injured tissue. The original nail or a protective substitute may be placed back under the nail fold. The decision should not be based on hematoma size alone.
Where and when to seek care
Minor injuries may be assessed in primary care. Suspected fracture, nail-bed laceration, deformity, deep wounds, or fingertip amputation should be evaluated in an emergency department or by a clinician experienced in pediatric hand injuries.
Urgent warning signs include uncontrolled bleeding, a pale, blue, cold, or numb finger, inability to move the finger, obvious angulation, nail-root displacement, exposed bone, partial amputation, major contamination, or severe uncontrolled pain.
Will the nail fall off and grow back?
The nail may remain in place or loosen over the following weeks. A new fingernail takes several months to grow. Temporary ridges, uneven color, and surface irregularity are common.
Persistent splitting, abnormal nail direction, recurrent swelling or drainage, or limited fingertip motion should be reassessed for nail-bed scarring, infection, fracture healing, or growth-plate injury.
Home care
Keep dressings clean and dry, follow wound-care instructions, elevate the hand, and monitor color, warmth, sensation, and movement. Avoid repeated alcohol or hydrogen peroxide on healing tissue unless specifically instructed.
Increasing redness, pain, pus, odor, fever, or new refusal to move the finger can indicate infection or another complication and requires review.
Key takeaways
A black nail after a door crush may be a simple bruise, but it may also hide a nail-bed laceration or fingertip fracture. Use cold, elevation, and pressure for first aid, avoid home drilling, and obtain prompt assessment when the nail root, skin, circulation, or alignment is abnormal.
Frequently asked questions
Does every large black area need drainage?
No. Pain, nail integrity, and fracture pattern matter more than color area alone.
Should I pull off the damaged nail?
No. Nail removal is performed only when needed for nail-bed or fracture treatment.
Does a normal X-ray mean the finger is fine?
Not necessarily. Nail-bed, tendon, nerve, and skin injuries still require examination.
How long does a fingernail take to regrow?
Complete regrowth usually takes several months.
Is a tetanus booster needed?
It depends on wound contamination and vaccination history. A clinician should assess this.
References
- Royal Children’s Hospital: Fingertip and nail injuries
- Royal Children’s Hospital: Thumb fractures
- Royal Children’s Hospital: Phalangeal finger fractures
Original educational content based on publicly available professional guidance. It does not replace clinical examination.
Pediatric surgery, trauma surgery, hyperbaric and diving medicine. Last updated: July 24, 2026.