I Hit My Finger and My Nail Is Black. What Now?

A fingernail that turns black after a hit is almost always blood pooled under the nail, not damage to the nail itself. It looks alarming, but most cases heal with simple care at home. The color leaves only as the nail grows, so the dark patch can last for months.12 Minute Medicine. Nail Trauma: Blood Under the Nail, Torn Nails and Healing

What the Black Color Under Your Nail Actually Is

A crush, such as a finger caught in a door or a hammer miss, pushes the nail down against the bone of the fingertip and breaks tiny blood vessels in the nail bed.2Life in the Fast Lane. Subungual Haematoma3PubMed Central. Nail bed injuries and deformities of nail Blood then collects in the thin space between the nail and the skin under it.4PubMed Central. Nail bed injuries and deformities of nail With nowhere to go, it presses on sensitive tissue, which is why it often hurts sharply and may throb.5Life in the Fast Lane. Subungual Haematoma6Harvard Health. Nail Trauma

The first hours can be the worst. Pain tends to build as blood keeps collecting, and throbbing that keeps you awake signals high pressure under the nail. Over the next few days, as swelling settles, the pain usually eases.

The spot can be a thin sliver or cover most of the nail, depending on how many vessels broke and how hard the blow was. Size alone can’t tell you whether the fingertip bone is broken; only an X-ray can.

Fresh blood looks dark red or purple under the nail.7Harvard Health. Nail Trauma Over days to weeks it turns dark brown or black.82 Minute Medicine. Nail Trauma: Blood Under the Nail, Torn Nails and Healing This is usually just the normal aging of trapped blood, not a sign the tissue is dying.

A skin bruise fades in a week or two because the body clears the blood away. Under the nail, the hard plate traps it, and the body doesn’t absorb it. It stays put and moves toward the tip as the nail grows.92 Minute Medicine. Nail Trauma: Blood Under the Nail, Torn Nails and Healing

What to Do at Home in the First Two Days

The standard care for this kind of injury is protect, rest, ice, compression and elevation, kept up for at least 48 hours.10fittoplay.org. First aid for hand injuries Start by holding the hand above heart level, which matters most in the first 48 hours, to ease pain and swelling.11Coastal Orthopedics. Is My Finger Broken or Bruised? Prop it on the back of a couch or a stack of pillows while you sit. When you’re up and walking around, rest your elbow on your chest with your fingers pointing up. A hanging fingertip fills with blood, which increases throbbing. At night, sleep with the hand on a pillow.

Wrap ice in a towel so it never touches the skin, and hold it on for 20 minutes every 1 to 2 hours during the first day.12Coastal Orthopedics. Is My Finger Broken or Bruised? Take it off if the fingertip goes numb or the skin looks white, even before 20 minutes are up, and wait before trying again. After the first day, ice 20 minutes 3 to 4 times a day until pain and swelling settle.13Coastal Orthopedics. Is My Finger Broken or Bruised? Acetaminophen, ibuprofen or naproxen can help control pain unless your doctor gives you something else or has told you to avoid them.14Coastal Orthopedics. Is My Finger Broken or Bruised?

Tape a light padded dressing over the nail so bumps don’t set the pain off again. Avoid gripping, typing hard or jamming the finger for a few days. If the skin is broken, keep it clean with soap and water and cover it with a bandage.

Don’t try to pierce the nail yourself. Heating a paperclip or drilling a hole at home risks infection and burns, and doctors use sterile tools and check for a fracture first. If the pressure pain is unbearable, that’s the cue to see a clinician.

If the nail is partly lifting, leave it in place. It protects the sensitive nail bed underneath while it heals. Trim any snagging edges gently and cover the nail instead of pulling it off.

Signs You Need a Doctor

Get care right away if any of these apply:

Severe, throbbing pressure pain in the first day or two is also worth a visit, since a clinician can often relieve it quickly. Small children’s fingertips are crushed often, and about half of those injuries include a broken bone.20PubMed. Pediatric Fingertip Injuries A young child with a crushed, black fingertip should be checked.

Urgent care or your GP can handle a closed nail with blood under it. An emergency room is better for exposed bone, deep cuts or a crooked finger. An X-ray is the usual way to check for a fingertip fracture.

Infection can show up in the days afterward. Redness, warmth and swelling should ease after the first couple of days, so increases after that are a warning sign. Pus, a bad smell, or throbbing that returns after improving suggests infection around the nail. Fever or a red streak running up the finger or hand needs prompt care, and people with diabetes or weakened immunity should not wait to see if it settles.

What a Doctor Can Do for the Pain and Pressure

The usual fix is trephination, making a small hole through the nail so trapped blood can escape.21PubMed. Controlled nail trephination for subungual hematoma The pressure drops and pain eases a lot over the following hours.22PubMed. Controlled nail trephination for subungual hematoma Because the hole goes through the nail only, not into the skin beneath, it causes little discomfort.23PubMed. Controlled nail trephination for subungual hematoma It’s quick, and it works best while the blood is still fresh and liquid.

At the visit, the clinician cleans the nail and may numb the finger, though the nail itself has no nerves. A heated tip or a tiny drill makes the hole in seconds, and dark blood seeps out. Many people feel the pressure ease right away. You go home with a dressing and instructions to keep it clean and dry.

Most people don’t need antibiotics after simple nail procedures. Doctors may give them to people with diabetes, weakened immunity or certain heart conditions, so mention any of these before treatment.

If the nail is intact, it doesn’t need to be removed, even with a large pool of blood.24PubMed Central. Approach to nail trauma for primary care physicians In children with an intact nail, draining alone healed as well as removing the nail and repairing the bed, regardless of hematoma size or fracture.25PubMed. Comparison of nail bed repair versus nail trephination for subungual hematomas in children The nail is lifted and the bed repaired if the nail itself is broken, the injury reaches the nail’s base, or a fracture needs stabilizing.26PubMed Central. Approach to nail trauma for primary care physicians Careful repair of the nail bed helps prevent later ridges or a narrowed tip.27PubMed Central. Nail bed injuries and deformities of nail

How Long Until Your Nail Looks Normal

Fingernails grow about 3.5 mm a month, roughly twice as fast as toenails.28PubMed. Growth rate of human fingernails and toenails in healthy American young adults The dark spot moves toward the tip and is trimmed away over a few months on a finger, a year or more on a big toe.292 Minute Medicine. Nail Trauma: Blood Under the Nail, Torn Nails and Healing A fingernail that comes off takes about 4 to 6 months to regrow, a toenail 12 to 18 months.302 Minute Medicine. Nail Trauma: Blood Under the Nail, Torn Nails and Healing

Where the spot sits tells you most of your timeline. A patch near the cuticle has the longest way to travel, so expect the longer end, while one near the tip leaves sooner. The spot isn’t fading but moving, so progress shows as normal pink nail appearing at the base.

Small blood spots usually leave the nail attached. A larger pool can lift the nail off its bed, and it may loosen and drop off weeks later. A new nail is often already growing underneath by then. Until the exposed bed toughens, keep it covered and moist with a dressing.

Most simple cases heal without lasting problems. After more serious nail bed injuries in children, a few had a sensitive fingertip or split nail (about 5% each), infection (about 4%), or a nail that didn’t stick down (2%).31Pediatric Emergency Care. Epidemiology and Outcome of Nailbed Injuries Managed in Children’s Emergency Department: A 10-Year Single-Center Experience These were most likely with badly crushed or torn nail beds and broken fingertip bones.32Pediatric Emergency Care. Epidemiology and Outcome of Nailbed Injuries Managed in Children’s Emergency Department: A 10-Year Single-Center Experience A lifting or misshapen nail can improve with time, often over several regrowth cycles.33PubMed Central. Nail bed injuries and deformities of nail

When a Dark Nail Might Not Be a Bruise

Blood under the nail is the most common cause of a dark nail.34PubMed Central. Optimal diagnosis and management of common nail disorders But many people don’t remember an injury, so a dark spot without a clear hit needs watching.35PubMed Central. Optimal diagnosis and management of common nail disorders The reliable sign is that blood moves out with the nail as it grows.36PubMed Central. Optimal diagnosis and management of common nail disorders If the color doesn’t grow out, a doctor should check for nail melanoma, a rare skin cancer.37PubMed Central. Optimal diagnosis and management of common nail disorders Bleeding doesn’t rule out melanoma, since melanomas can bleed too.38PubMed Central. Optimal diagnosis and management of common nail disorders

Warning signs of nail melanoma include:

Fungus looks different. Trauma appears suddenly after an injury, usually in one nail, and is purple, black or red.47Foot & Ankle Specialists of Northern New Mexico. Toenail Trauma or Fungus? How to Tell the Difference Fungus comes on gradually, often spreads to several nails, and looks yellow, white or brownish with crumbly edges.48Foot & Ankle Specialists of Northern New Mexico. Toenail Trauma or Fungus? How to Tell the Difference

To track a dark spot at home, take a clear photo now, in the same light and from the same angle, and repeat it every couple of weeks. Note how far the patch sits from the cuticle each time. A clear band of normal nail appearing at the base means the dark area is blood growing out. If no gap appears after a month or two, book a visit.

A dermatologist looks at the nail closely with a lighted magnifying tool. Blood usually appears as an even color or small dots or globules, which looks different from a pigmented band. If they are still unsure, they may take a small sample of the nail area to examine under a microscope.