When an impact causes your finger to hurt and your nail to turn dark, it indicates bleeding beneath the nail plate. This common injury, known as a subungual hematoma, results from trauma. The discoloration and discomfort signal that blood has collected in the confined space under your nail. Understanding appropriate care steps can help manage this condition effectively.
Understanding Your Black Nail
A black or dark-colored nail after an injury is caused by a subungual hematoma. This occurs when blunt force trauma, such as hitting your finger with a hammer, damages blood vessels in the nail bed. These injured vessels leak blood, which then pools in the tight space between the nail plate and the underlying tissue. Since there is no room for the blood to disperse, it creates pressure and causes pain.
The characteristic dark coloration, ranging from red or purple to dark brown or black, results from the blood clotting and breaking down over time. Initially, the blood may appear reddish or purplish, gradually darkening as it clots. This pooling of blood can also cause the nail to feel sensitive or tender to the touch.
When Professional Help is Needed
While many black nail injuries are minor, some situations warrant immediate medical attention. Seek professional help if you experience severe, unrelenting throbbing pain that does not subside, as this may indicate significant pressure. A doctor may perform trephination to drain the blood and relieve this pressure. This procedure involves creating a small hole in the nail, which provides immediate pain relief.
You should also consult a healthcare provider if the dark discoloration covers more than 25-50% of your nail, especially if accompanied by pain. Signs of infection, such as increasing redness, warmth, swelling, pus draining from under the nail, or fever, require prompt medical assessment. If you suspect a bone fracture, indicated by a deformed finger, extreme pain, difficulty moving the finger, or significant bruising, an X-ray may be necessary. If the nail plate is significantly detached or torn, or if there is a deep cut to the nail bed, a medical professional can assess the damage and determine if stitches or complete nail removal are needed.
Caring for Your Injured Finger and Nail
For minor black nail injuries without the need for professional intervention, several home care strategies can help manage discomfort and promote healing. Immediately applying ice, wrapped in a cloth, for 10-20 minutes at a time can help reduce swelling and pain. Elevating the injured hand above heart level can also aid in reducing swelling by assisting fluid drainage. Over-the-counter pain relievers, such as ibuprofen, can help alleviate pain and reduce inflammation.
As the nail heals, the discolored blood will gradually grow out with the new nail. The old, damaged nail may separate and eventually fall off as a new, healthy nail grows underneath. This natural process can take several months, around six to nine months for a fingernail to fully grow out.
It is important to keep the injured area clean and dry to prevent infection during this healing period. Covering the nail with a clean, dry bandage protects the growing nail. While the new nail emerges, protect it from further injury to ensure proper growth.