Subungual hematomas, commonly known as bruised fingernails or toenails, result from injury -- as well as certain medications and medical conditions -- such as cancers and autoimmune disorders. In most cases, subungual hematomas are not dangerous. They are, however, extraordinarily painful. The pooled blood trapped under the nail generates pressure on the nail bed. Because the nail bed contains many nerves and blood vessels, this pressure can be very painful. If the bruise covers less than 25 per cent of the nail, you can treat the hematoma at home. If the hematoma covers more than 25 per cent of the nail, see your doctor. Using a process called trephination, doctors can drain the subungual hematoma to relieve the pressure. The doctor will also check to see if you have an injury to the bone or nail bed.
Ice the affected nail. To protect your skin, place a towel or washcloth between your skin and the ice pack. Ice the injury every hour, for 20 minutes.
Elevate the injury by keeping it above your heart. Lie down and prop your hand or foot up with pillows.
Take an anti-inflammatory such as ibuprofen. Because dosage varies depending on the type of anti-inflammatory, follow the instructions included with your medication.
Wait for several weeks. Eventually, the affected nail will generally fall off because the blood separates from the nail bed. Once the nail has fallen off, a new nail will grow in its place. This process can take as little as eight weeks for a fingernail, or as long as six months for a toenail.
Call your doctor if your nail falls off soon after the injury and bleeds. If your finger or toe turns red and swells, call your doctor. These are signs of more serious injuries.