What Happens When You Hit Your Fingernail Really Hard?

Hitting your fingernail extremely hard typically results in a subungual hematoma, which is essentially a bruise forming under the nail. This happens because the direct trauma damages the delicate blood vessels located just beneath the nail plate.

Understanding a Subungual Hematoma

When a significant force, such as from crushing or slamming, impacts your nail, it causes these tiny blood vessels to rupture. The blood then pools in the confined space between the nail plate and the nail bed, leading to the characteristic discoloration and pain. Despite how painful they can be, subungual hematomas are generally considered minor injuries.

Key Symptoms and Appearance

The immediate and subsequent signs of a severe nail strike include:

• Intense Pain: Often described as throbbing, the pain is caused by the pressure of the accumulated blood under the rigid nail.
• Discoloration: The nail area underneath will quickly turn red, then progress to dark purple or black as the blood clots and oxidizes. The size of the discolored area depends on the extent of the bleeding.
• Pressure Sensation: A feeling of fullness or throbbing pressure under the nail is common due to the trapped blood.

What to Expect in the Short Term

While initially very painful, the discomfort from a subungual hematoma typically begins to improve within a few days as the initial swelling subsides and the body starts to resorb the blood. The discoloration, however, will remain until the nail grows out, which can take several months.

When to Seek Medical Attention

Although most nail bruises are minor, certain signs indicate that a medical professional should evaluate the injury:

• Severe, Unrelenting Pain: If the pain is excruciating and doesn't improve with home care, or if it's accompanied by severe throbbing that indicates significant pressure.
• Extensive Hematoma: If the bruise covers more than 25-50% of the nail, or if it's expanding rapidly.
• Signs of Infection: Redness, increasing warmth, swelling, pus, or fever around the injured finger.
• Nail Detachment: If the nail is lifting significantly from its bed or appears completely detached.
• Suspected Fracture: If the finger appears deformed, or if there's significant pain in the bone, suggesting a potential bone fracture in the underlying finger.
• Jagged Nail Edges: If the nail is badly split or has sharp edges that could snag or cause further injury.

Home Care and Relief Strategies

For most minor subungual hematomas, these steps can help manage symptoms:

• Apply a Cold Compress: Immediately apply ice wrapped in a cloth to the injured area to reduce swelling and numb the pain.
• Elevate the Hand: Keep your hand elevated above your heart to help reduce blood flow to the area and minimize swelling.
• Over-the-Counter Pain Relievers: Medications like ibuprofen or acetaminophen can help manage pain and inflammation.
• Protect the Injured Nail: Cover the nail with a bandage to prevent further injury or snagging.

The Healing Process

The blood trapped under your nail cannot simply drain away on its own unless the nail is pierced (a procedure called trephination, which should ideally be done by a medical professional to avoid infection). Instead, the discolored blood will slowly grow out with the nail plate. This is a gradual process that can take several months for a fingernail to fully replace itself from base to tip. As the new, healthy nail grows, the bruised area will move forward until it eventually reaches the tip and can be trimmed away.

Signs of a Nail Injury

For more in-depth information on how to care for various nail injuries, you can consult reliable health resources. Learn more about nail injuries