Finger Injury First Aid: Slammed Fingers, Blood Under the Nail, Jammed Fingers and Fingertip Cuts

Quick answer: for a slammed or jammed finger, remove rings right away, apply a cloth-wrapped cold pack for 15 to 20 minutes at a time, raise the hand above the heart and rest it. Clean any cut and press firmly on bleeding with clean gauze. Get medical care if the finger looks bent or out of place, cannot straighten at the tip, has a deep or gaping cut, has painful blood under more than a small part of the nail, or numbness. If part of a finger is cut off, call 911, control bleeding, and bring the part wrapped in damp gauze inside a sealed bag placed on ice.

Fingers get caught in heavy apartment doors, car doors, folding chairs and kitchen drawers. They get jammed playing ball, cut while cooking and crushed when moving furniture. Most finger injuries heal well with simple care, but some need a doctor to protect how the hand works later. This article is part of our emergency first aid guide for city households.

Sources: American Society for Surgery of the Hand (ASSH) patient education on fingertip injuries, mallet finger and jammed fingers; American Academy of Orthopaedic Surgeons (AAOS) OrthoInfo; American Academy of Pediatrics (AAP) HealthyChildren.org; American Red Cross first aid guidance; MedlinePlus (U.S. National Library of Medicine). This article is general information and not a substitute for medical care.

First Steps for Any Finger Injury

Whatever the injury, a few steps come first:

1. Remove rings immediately. Fingers can swell quickly, and a ring can cut off blood flow. If it will not come off, a little soap or lotion can help. If it still will not move and the finger is swelling, get medical care, since emergency departments can cut rings off safely.
2. Check for bleeding. Press firmly with clean gauze or cloth.
3. Look at the shape. Is the finger crooked, bent at an odd angle or rotated?
4. Check movement and feeling. Can the person bend and straighten each joint? Is there numbness or tingling?
5. Cool and raise. Use a cold pack wrapped in a thin cloth and keep the hand raised above the level of the heart.

Fingers Slammed in a Door

Door injuries are among the most common finger injuries in children and adults. The AAP notes that doors are a frequent cause of finger injuries in young children, and these can range from bruises to fractures and fingertip amputations.

What to do

• Apply a cold pack wrapped in cloth for 15 to 20 minutes at a time, several times during the first day.
• Raise the hand to help reduce swelling and throbbing.
• Clean any broken skin with clean water and cover it with a bandage.
• Use an over-the-counter pain reliever if needed, following the label.

When to get care

Seek medical care if:

• The finger looks deformed
• A cut is deep, gaping or will not stop bleeding after 10 minutes of firm pressure
• The nail is torn off or the nail bed is cut
• Pain is severe or does not improve
• There is a large area of blood under the nail
• The person cannot bend or straighten the finger normally

Blood Under the Nail

A crushing injury can cause bleeding under the fingernail, called a subungual hematoma. The nail turns dark red, purple or black, and the pressure can cause intense, throbbing pain.

A small spot of blood usually needs only cold, elevation and time. As the nail grows, the dark spot moves forward and eventually grows out, which can take several months.

If the pain is severe or the blood covers a large part of the nail, see a doctor. A health care provider may relieve the pressure by making a tiny hole in the nail, a quick procedure that often brings immediate relief. Do not try this at home with a heated paper clip or pin, which risks burns and infection. A doctor can also check whether the bone underneath is broken or the nail bed is cut.

Jammed Fingers

A jammed finger happens when the tip of the finger is pushed back toward the hand, often by a ball. It can sprain the ligaments around a joint, usually the middle joint, and cause pain, swelling and stiffness.

Home care for a mild jam

• Cold pack for 15 to 20 minutes at a time
• Elevation
• Gentle movement as pain allows
• “Buddy taping” to the neighboring finger for support, with a small pad of gauze between them

When it may be more than a jam

A jammed finger can also involve a fracture, dislocation or tendon injury. Get it checked if:

• The finger looks crooked or out of place
• You cannot fully bend or straighten it
• Swelling and pain are severe or do not improve within a few days
• There is numbness

Do not try to pull a dislocated finger back into place yourself. Splint it in the position you find it, and go to an urgent care center or emergency department.

Mallet Finger

Mallet finger is an injury to the tendon that straightens the tip of the finger. It often happens when a ball strikes the fingertip or when the fingertip is jammed while tucking in sheets. The fingertip droops and cannot be straightened on its own, though it can be pushed straight with the other hand.

The ASSH notes that mallet finger is usually treated with a splint that keeps the fingertip straight for several weeks. It is important to see a doctor soon, because the splint must stay on continuously for the tendon to heal. Bending the tip even once during treatment can set healing back.

Broken Fingers

Signs of a broken finger include:

• Pain and swelling that do not improve
• Bruising
• Deformity, such as a bend or rotation
• Trouble moving the finger
• Tenderness over the bone

One way doctors check for rotation is to have you make a gentle fist. If one finger crosses over another, the bone may be rotated, which needs treatment to heal correctly. If you suspect a break, splint the finger by buddy taping it or using a padded stick, apply cold and get medical care. Our guide to sprains, strains and broken bones covers splinting.

Fingertip Cuts

Kitchen knives, mandolines, can lids and broken glass are common causes of fingertip cuts.

1. Wash your hands if possible, and put on gloves.
2. Rinse the cut with clean running water.
3. Press firmly with clean gauze for at least 10 minutes without lifting to check.
4. Raise the hand above the heart.
5. Once bleeding stops, apply ointment and a bandage.

Get care for a cut that is deep, gaping, longer than about half an inch, has jagged edges, was caused by a dirty or rusty object, involves the nail bed or causes numbness, since nerves in the fingers can be damaged. Ask about a tetanus shot if it has been more than five years since the last one for a dirty wound. Our guide to cuts and scrapes wound care explains how to clean wounds and watch for infection.

For heavy bleeding, apply firm, direct pressure and call 911 if it will not stop. Our guide to Stop the Bleed basics explains how to control serious bleeding.

If Part of a Finger Is Cut Off

A fingertip amputation is an emergency. Fast, careful action improves the chance that surgeons can repair the finger or reattach the part.

1. Call 911 or get to an emergency department right away.
2. Control bleeding by pressing firmly on the injury with clean gauze and raising the hand.
3. Find the amputated part. Gently rinse off dirt with clean water if needed, but do not scrub.
4. Wrap the part in gauze or a clean cloth moistened with clean water or saline.
5. Place it in a sealed plastic bag.
6. Put the bag on ice or in a container of ice water. Do not let the part touch ice directly, and do not freeze it.
7. Bring the part with you to the hospital, labeled with the person’s name and the time of injury.

Do not throw away any part, even if it seems too small or damaged. Let the medical team decide what can be done.

Caring for a Finger While It Heals

Most finger injuries need some care over the following days and weeks, even after the first aid is done.

Keep the hand raised as much as you can during the first two days, especially at night, by resting it on a pillow. Swelling is often worst in the first 48 hours, and elevation helps reduce throbbing. Continue cold packs for 15 to 20 minutes at a time during this period.

If a finger is buddy taped, change the tape when it gets wet or dirty, and keep a small piece of gauze between the fingers so the skin does not stay damp and break down. Check that the tape is not too tight. A finger that turns pale, blue or cold, or that tingles, needs looser tape.

Once a doctor says it is safe, gentle movement helps prevent stiffness. Fingers can become stiff quickly when they are kept still, and stiffness after a jammed or broken finger is common. Some people need a few sessions with a hand therapist to regain full motion, especially after a fracture or tendon injury.

Watch cuts for infection, including increasing redness, warmth, swelling, pus, red streaks or fever. Fingertip infections can spread into the deeper tissues of the hand, so do not wait to get care if these signs appear.

Finger Injuries at Work and While Moving

Moving day in a city often means carrying furniture through narrow stairwells, heavy building doors and tight elevators, which is a common time for pinched and crushed fingers. Wear sturdy work gloves, keep fingers on the sides rather than the bottom of heavy items when setting them down, and agree on clear signals with the person carrying the other end. Prop doors open with a door stop rather than holding them with a hand or foot. Take breaks when your grip starts to tire, since tired hands are more likely to slip, and keep a small first aid kit with gauze, tape and a cold pack easy to reach on moving day.

Finger Injuries in Children

Young children often catch fingers in door hinges, the gap on the hinge side of a door, as well as in the closing edge. Children may not be able to say how bad it hurts, so watch for:

• Refusing to use the hand
• Swelling, bruising or a dark nail
• A crooked finger
• Crying that does not settle

Seek medical care for any suspected fracture, nail bed injury or deep cut in a child, since growing bones and nail beds need correct treatment.

Preventing Door Injuries at Home

• Install door stops or finger-pinch guards on doors children use.
• Use hinge-side guards to cover the gap where tiny fingers can get crushed.
• Hold heavy building doors open for children instead of letting them push through.
• Teach children to keep hands off door edges and hinges.
• Watch fingers when folding chairs, strollers and step stools.
• Be careful with car doors, especially when children are getting in and out.

Frequently Asked Questions

How long does a slammed finger take to heal?

Bruises usually heal in a week or two. Blood under the nail can take months to grow out. A fracture usually takes several weeks and needs medical care.

Should I pop a blood blister under my nail?

No. Do not pierce the nail at home. A doctor can relieve the pressure safely if needed.

Can a fingernail grow back after it falls off?

Usually yes, if the nail bed is not badly damaged. Fingernails can take several months to grow back fully.

Is it OK to buddy tape a jammed finger?

Buddy taping can support a mild sprain. If the finger is crooked, very swollen or cannot move normally, get it checked first.

When should I go to the ER for a finger injury?

Go for severe bleeding, an amputation, a finger that looks deformed, a cut with numbness, or a nail bed injury.