How to Treat a Smashed Finger

Just the mention of a finger getting squashed in a door or getting pounded by a hammer is enough to make most people cringe. The throbbing pain of a smashed finger is highly unpleasant, to say the least.

What to Do Immediately After You Smash Your Finger

Assuming you've extricated the finger (this would be step one), there are a few things you can do to alleviate your excruciating pain.

Ice it. Use an ice pack to reduce pain and swelling. Keep the ice on it for 15 minutes a couple of times an hour for the first few hours after smashing it. Don't keep ice on too long or you can develop frostbite.
Elevate it. Letting your hand dangle at your side after smashing your finger will simply increase swelling and that uncomfortable throbbing. Hold it up to reduce the pressure in there.
Use it. I don't expect you to start lifting weights with your injured finger, but keep it moving. If you can't move your finger or if you can't feel it after a few minutes (you have to give the throbbing time to go away), then you should visit the doctor.
Take a pill. Over-the-counter painkillers can help relieve the constant reminder that you didn't move quick enough.

What Not to Do

Don't wrap a smashed finger. We already struggle to get blood flowing to the tips of our fingers and toes on a good day.

Wrapping injured fingers and toes can lead to more damage when vital oxygen and nutrients can't get to the tips.

Covering a finger injury is not a bad idea, especially if you're still working, but keep it loose.

What to Do in a Day or Two

Smashing your finger is just the beginning. After a day or two, blood will likely start to build up under your nail.

You might see the nail turning color—usually dark blue or black—and feel a lot of pressure. This is what happens when a bruise is contained in the tiny space at the tip of a finger. Letting the pressure out will help the healing process and significantly reduce the pain.

Make sure you touch bases with a healthcare provider before trying this. You'll need a lighter or a candle, a pair of pliers, and either a clean, sterile paper clip or a safety-pin. From here on out, we'll only refer to your tool of choice as a paperclip, but it doesn't matter which one you use.

Wash the finger thoroughly. You do not want to develop an infection in the tip of your finger.
Open the paper clip so that you have a straight edge.
Holding the paperclip with the pliers, heat the tip in the flame until it is red-hot.
Carefully touch the red-hot tip of the paperclip to the area of the nail where most of the blood is collected (usually the darkest spot on the nail) and put just a little pressure on it. Keep it there until the paperclip burns through the nail. Don't push hard; just let the heat do the work.

The blood might gush out of the hole once the paperclip burns through. In time, if the hole closes up again, you can repeat the procedure.

This procedure shouldn't hurt much if at all. If the pain is too severe to try this, you'll need to see a doctor.

When to Go to the Doc

In most smashed finger cases, you don't need to run to the ER. Occasionally, the finger might be broken.There are exceptions to any rule, however, so visit your favorite healthcare provider if you have any of the following:

Deformity
Numbness before you put any ice on it (especially if you don't even feel throbbing)
Signs of infection

If your fingernail falls off, don't panic. It's not ideal, but chances are very good it will grow back without a problem. While it doesn't necessarily mean you should see a doc, a missing fingernail is at least worth a call to the office.

Sources:

Nelson SW, Gibbs MA. Hand and wrist injuries. In: Adam JG, ed. Emergency Medicine: Clinical Essentials. 2nd ed. Philadelphia, PA: Elsevier Saunders; 2013:chap 89.

NIH U.S. National Library of Medicine. Smashed Finger. 2015.