A subungual hematoma is a condition in which there is bleeding under the fingernail or toenail. Usually caused by a crush injury, a subungual hematoma can cause symptoms such as intense pain and throbbing as blood collects under the nail.
Unless there are also broken bones or damage to the nail bed and/or surrounding tissues, a subungual hematoma is seldom worrisome.
Causes of a Subungual Hematoma
Most often, a subungual hematoma is an immediate consequence of a crush-type injury involving the tip of the finger or toe. Common examples include:
- Slamming your finger in a car door or house door.
- Hitting your finger with a heavy object such as a hammer.
- Dropping a heavy object such as a dumbbell on your toe.
- Stubbing your toe on a hard surface.
In some cases, a tumor under the nail can cause a darkened area that can resemble a subungual hematoma. If you have a darkened area under a nail, and no history of trauma to the nail, you should have it evaluated by your health care provider. The spot will grow out with the nail if it is a subungual hematoma. It will stay in the same spot under the nail if it is a tumor.
Symptoms of a Subungual Hematoma
The most common symptom of a subungual hematoma is severe, throbbing pain generated by the pressure of blood collecting between the nail and the nail bed. Other symptoms include:
- A dark-colored discoloration (red, maroon, or purple-black) under all or part of the affected nail.
- Tenderness and swelling of the tip of the affected finger or toe.
Diagnosis of a Subungual Hematoma
If a subungual hematoma was caused by a severe blow to a finger or toe, either seek immediate medical attention from your health care provider or go to an emergency room. In addition to the hematoma, you may have broken bones or serious damage to the nail bed and/or surrounding tissues.
The health care provider will examine your nail and you’ll likely undergo an X-ray to either confirm or rule out a bone fracture or other injury.