Bruising of the nail (subungual hematoma)

Hands | Dermatology | Bruising of the nail (subungual hematoma) (Disease)


The fingernail is an important part of fingertip function. It provides support for the finger pad and improves sensation. The toenail functions in a similar manner in the foot.

Causes and Risk factors

Nails bruise because blood vessels in the skin underneath the nail either burst due to pressure from an injury or chronic stress on the nail, or are severed by a cut in the skin underneath the nail. Bruised nails are common, and can be due to a number of different reasons.

Most injuries to the nail arise from: crushing forces, such as hammers, doors slamming on fingers, human bites, or machinery, slicing or cutting, such as knives, box cutters, or machinery and tearing or ripping, such as stubbing a toe or catching a fingernail on an object. The entire finger or toe throbs with every heartbeat and is painful to touch or even move through the air. As blood pools under the nail plate, regardless of the cause, it will turn the color of the nail blue, purple, or eventually black. This color will stay in the nail until the new nail grows outward, where the discolored area will be pushed slowly towards the toe tip.

Diagnosis and Treatment

Larger bruises may require removal of the nail to help drain the blood and prevent infection. The nail will eventually grow back. Melanoma of the nail, while uncommon, it can look identical to a common bruise, and needs specialist medical evaluation to make a proper diagnosis. ...