Subungual Hematoma

Why Immediate Medical Attention is Needed for Nail Bruising

Most people have experienced the anxiety caused by a strong hit of the big toe against furniture or the catching of a finger in a closing door. The result can be a bruised nail, which requires special care and patience until it returns to its natural state.

“Most injuries affect the nail plate (the hard part of the nail) and the underlying tissues. The development of a hematoma (bruising) is a common consequence. However, other issues may occur, such as cracking of the nail plate or even nail loss (immediately or weeks later),” notes Dr. Markos Michelakis, dermatologist-venereologist at EDOEAP.

Contrary to what many believe, bruising does not develop on the nail but under it. “A subungual hematoma occurs when an injury causes trauma to the nail phalanx of one or more fingers, leading to blood collecting between the nail plate and the nail matrix. The matrix is the part at the base of the nail (towards the joint of the nail phalanx) from which the nail grows,” explains Dr. Michelakis. “The hematoma results from rupture of the capillaries in the area.”

The subungual hematoma can be extremely painful during the first days after the injury, as there is no space for the trapped blood to escape. At this stage, it is essential for the patient to see a dermatologist to drain the hematoma.

“If you see blood or bruising under the nail after an injury, seek medical advice within 48 hours,” recommends the specialist. “The dermatologist will perforate the nail and drain the hematoma, saving you from many problems.”

The first issue you will avoid is the continuation of pain. Pain is usually not due to the injury itself but to the trapped blood, which exerts pressure on the nerves in the area. The pain can be unbearable and interfere with daily activities.

Without immediate drainage, the trapped nerves may take weeks to return to their normal state. With nail perforation, however, this happens in a few minutes. The perforation procedure is painless because the nail has no nerve endings. Without it, the hematoma can clot, creating a mass under the nail that can cause weeks of pain.

After perforation, the nail must be kept clean and dry. “Avoid bubble baths, prolonged showers, and swimming until your doctor tells you it is safe,” advises Dr. Michelakis. “Exposing the nail to water prematurely increases the risk of infection.”

Another risk when a subungual hematoma is not treated promptly is that any fracture of the nail phalanx or damage to the nail matrix may go unnoticed. Fractures in a small finger bone are difficult to detect without an X-ray. Fractures are more likely when the subungual hematoma is extensive.

Without proper care, even small fractures may not heal correctly, potentially causing the affected finger to no longer function normally or leading to long-term pain.

Similarly, if there is damage to the nail matrix, stitches may be required. This is necessary because damage to the matrix affects nail growth and can leave you with a nail completely different from normal. Without treatment, permanent deformation, loss of normal contour, or permanent thickening of the nail can occur. This risk is usually associated with large subungual hematomas (those covering almost the entire surface under the nail).

The subungual hematoma can also cause nerve damage in the area, leading to long-term symptoms such as tingling, weakness, and pain. Small nerve injuries may be managed with rest and a special splint. Larger or more complicated injuries may require physiotherapy or even surgical repair, although this is rare.

Another risk is nail loss. This can happen during the injury or later. If you see the nail separating from its base, do not try to remove it yourself. Gently reposition it, wrap it with a clean gauze, and go immediately to a doctor for care. If removal is necessary, the doctor will do it safely.

After a nail injury, in addition to immediate medical advice, it is very important to monitor for symptoms of infection. This is more likely if the nail plate has cracked or detached. Consult your doctor immediately if you notice redness in the finger, red streaks developing, warmth when touching the nail or surrounding skin, pain or unbearable pain, or fever/feeling unwell.

Immediate medical attention is also essential if nail bruising develops without prior trauma. “Discolorations of unknown origin may be harmless moles or indicate a condition that requires urgent treatment, including skin cancer,” emphasizes Dr. Michelakis.

In any case, remember that after a nail injury, it may take many months for full recovery. Fingernails grow about 3.5 millimeters per month, while toenails grow about 1 millimeter per month. Therefore, it may take 6–12 months for the entire nail to replace and to see whether there is permanent damage or not.