Nail bed injuries are a type of fingertip injury, which is the most common type of hand injury seen in hospital emergency rooms. They can be minor or they can also be very painful and uncomfortable, even limiting your finger movement.

Nail bed injuries can occur many ways. Often, they happen when your nail’s caught between two objects or hit by something heavy, such as being slammed in a door, having something being dropped on it, or being hit by a hammer. They can also be caused by cuts, such as from a knife or a saw.

Nail bed injuries are almost always treatable but in rare cases can cause nail deformities.

When your fingertip or your nail bed is pinched, crushed, or cut, it causes a nail bed injury.

Crushing can happen when your finger gets caught between two objects or in a doorway. Heavy objects falling on your finger can also cause injuries to the nail bed, as can being hit by a hammer.

Cuts to your fingertip, nail bed, or the tendons that you use to straighten and bend your fingertip can all cause nail bed injuries. Cuts to nerve endings in your fingertip can also cause nail bed injuries.

Nail bed injuries can cause:

  • blood to pool under your nail
  • your nail to crack into pieces
  • your nail to be torn off

There are many types of nail bed injuries, including:

Subungual hematoma

A subungual hematoma is when blood gets trapped under your nail bed. It’s usually caused by your nail getting crushed or hit by a heavy object. Symptoms include throbbing pain and your nail turning black and blue. This usually looks like a bruise under your nail.

Nail bed laceration

A nail bed laceration is when your nail and the underlying nail bed get cut. It’s usually caused by a saw or knife but can also be caused by a crushing injury. If you have a nail bed laceration, it’s likely to bleed. You’ll be able to see the cut through your nail. As it heals, you might have a large bruise.

Nail bed avulsion

A nail bed avulsion is when your nail and part of your nail bed are pulled away from the rest of your finger. It commonly happens to your ring finger and is caused by your finger getting stuck or jammed in something. Nail bed avulsions are very painful and cause your finger to swell. Finger fractures are also common with this type of injury.

If you have a nail bed avulsion, your nail will have to be removed if it hasn’t come off during the injury.

Other injuries

There are also nail bed injuries that affect more than your nail bed, such as a fingertip fracture or amputation.

Repairing a nail bed injury will differ depending on the type of injury. If your injury is serious, your doctor might take an X-ray to check for broken bones. You may also get anesthesia so your doctor can look at your nail more closely and treat your injury without causing more pain.

Common treatment for nail bed injuries include:

  • For subungual hematomas. This can be drained through a small hole in your nail, usually made with a needle. This also relieves pain and pressure. If the subungual hematoma covers more than 50 percent of your nail, you might need to have the nail removed so you can get stitches.
  • For nail bed lacerations. This injury might require stitches. If the cut is serious, your nail might have to be removed. It should grow back.
  • For nail bed avulsions. This injury requires removing your nail. If you also have a finger fracture, it will need to be splinted. You might need a splint for up to three weeks, depending on the seriousness of the injury.

Many injuries to your nail bed can be fully repaired. For example, your nail should return to normal after a subungual hematoma is drained. However, some severe injuries can lead to a deformed nail. This is more likely when the base of your nail bed is injured.

The most common complications of nail bed injuries are hook nail and a split nail. A hook nail occurs when your nail doesn’t have enough bony support and curves around your finger. It can be treated by removing your nail and trimming some of the nail matrix, which is the tissue your nail rests on.

A split nail happens because your nail can’t grow over scar tissue. It’s treated by removing the nail that’s already grown and treating or removing the scar so new nail can grow properly.

If all or part of your nail is removed, it will grow back. It takes approximately a week for a fingernail to start growing back and three to six months for it to totally grow back. After the nail’s removed, you’ll need to keep your fingertip covered while your nail starts to grow back.

Many nail bed injuries require a doctor. However, there are several steps you should take before seeing a doctor when you injure your nail bed:

  • Remove all jewelry from your hands. If your finger’s too swollen to get a ring off, call your doctor immediately.
  • Gently wash the injury, especially if it’s bleeding.
  • Apply a bandage if necessary.

If your injury is minor, you may be able to treat it at home. For example, if your subungual hematoma is small (one-fourth the size of your nail or less), you don’t need to see a doctor. In addition, if your nail is completely removed and the nail bed or rest of your finger isn’t injured, you may not need to see a doctor.

If you have a deep cut in your nail bed, you should see a doctor, especially if it doesn’t stop bleeding. Subungual hematomas that cover more than a quarter of your nail also need medical treatment.

If your finger is very swollen or painful, or if you think it’s fractured, you should see your doctor for an evaluation.