A bruise under the toenail, medically termed a subungual hematoma, occurs when blood vessels beneath the nail plate rupture and leak blood into the confined space of the nail bed. This trapped blood causes the characteristic dark discoloration, which can range from red to purple or black. The injury is typically caused by trauma to the toe. While pain often subsides quickly, the primary concern is how long the discoloration will last, which is directly tied to the slow rate of natural toenail growth.
Identifying the Cause and Symptoms of a Toenail Bruise
A subungual hematoma is almost always the result of an injury that damages the blood vessels in the nail bed. The cause can be a single, acute incident, such as dropping a heavy object onto the toe or forcefully stubbing the toe. This crushing trauma causes immediate bleeding and pressure beneath the nail.
The injury can also result from repetitive micro-trauma, which is common in athletes like runners or hikers. This occurs when the toes repeatedly slide forward and impact the inside front of a shoe, often due to ill-fitting footwear. The constant, minor pressure eventually leads to blood vessel damage and pooling of blood.
The most noticeable symptom is the dark discoloration of the nail, which may appear immediately or develop over a few hours. The color usually starts as reddish-purple and progresses to dark brown or black as the blood clots and dries. This appearance is often accompanied by intense, throbbing pain caused by the pressure of the accumulating blood pressing against the sensitive nail bed. The pressure can also cause the nail plate to lift slightly.
The Healing Timeline: How Long Until It’s Gone?
The healing process for a bruised toenail is fundamentally different from a bruise on the skin, which fades over days or weeks as the body reabsorbs the blood. The blood trapped beneath the toenail cannot be reabsorbed quickly or easily because the nail plate acts as a barrier. Consequently, the discolored area will remain visible until the toenail naturally grows out and pushes the bruised section forward.
Toenails grow at an exceptionally slow pace, generally much slower than fingernails. The complete replacement of a toenail, from the base to the tip, typically takes an extended period. For most people, the full regrowth cycle ranges from six to nine months, sometimes taking up to a full year or 18 months, especially for the big toe. This extended timeline is why the bruise appears to last so long.
As the nail grows, a new, healthy section of clear nail will emerge from the cuticle area at the base of the toe. The dark, bruised section will slowly migrate toward the tip of the toe over the course of several months. The size of the bruise dictates how long it will take to reach the end of the nail, where it can finally be trimmed away. If the trauma was severe enough to cause the entire nail to detach, a new nail will replace it, which still follows the same slow growth schedule.
Immediate At-Home Care and Management
Initial management of a bruised toenail focuses on reducing swelling and alleviating the immediate pain caused by the pressure. Applying the R.I.C.E. protocol—Rest, Ice, Compression, and Elevation—is the standard non-invasive approach immediately following the injury. Resting the foot and avoiding activities that put pressure on the toe are important to prevent further damage.
Applying ice wrapped in a thin cloth for 15 to 20 minutes several times a day helps constrict blood vessels, minimizing swelling and reducing throbbing pain. Elevating the foot above the level of the heart uses gravity to assist in reducing blood flow to the injured area, thereby decreasing inflammation. While compression is sometimes recommended, care must be taken not to apply too much pressure, which could increase discomfort.
Over-the-counter non-steroidal anti-inflammatory drugs (NSAIDs) can be taken to manage pain and residual swelling. During the healing process, wearing comfortable, wide-toed shoes is recommended. Properly fitting shoes prevent the toe from hitting the front, which is a source of repetitive trauma that can exacerbate the injury.
When to Seek Medical Help
While many subungual hematomas can be managed at home, certain signs indicate the need for professional medical intervention. Severe throbbing pain that does not improve with rest, ice, and over-the-counter medication suggests significant pressure buildup. A healthcare provider can perform trephination, which involves creating a small hole in the nail to drain the trapped blood and instantly relieve the pressure.
Medical attention is necessary if the hematoma covers more than 50% of the toenail surface, as this increases the risk of damage to the underlying nail bed tissue. Signs of infection, such as increasing redness, warmth, swelling, pus, or red streaks extending from the toe, require immediate care. These symptoms suggest bacteria may have entered the injured area.
Consulting a doctor is important if there is a possibility of a fracture in the underlying toe bone, which is a risk with severe crushing injuries. Any dark discoloration under a toenail that appears without a clear history of trauma should also be evaluated, as this could rarely be a sign of other conditions.