Frostbite—ER or Not?

What Is Frostbite?

Interviewer: It's time for another edition of "ER or Not?" where we help you to figure out if it's a reason to go to the ER, head to an urgent care, see a provider, or handle it on your own.

This time, we're joined by Dr. Graham Brant-Zawadzki, an emergency medicine physician with a subspecialty in prehospital and wilderness medicine.

Today's question. You've been outside in freezing temperatures, maybe shoveling snow, maybe hiking in the backcountry, skiing, and now your toes are numb. Hours later, they're maybe still hurting. They might even look a little bit pale or maybe even gray. Is it frostbite? And if it is, should you go to the ER now?

Dr. Brant-Zawadzki, let's start with what frostbite is. What happens to the body when that happens, and at what point is it frostbite rather than just being really cold?

Dr. Brant-Zawadzki: Frostbite comes from prolonged cold exposure. And it comes when the tissues and fluids within the body actually freeze and cause crystal formation. So we generally see it in the tips of the fingers, tips of the toes, the nose, anywhere where our body has the most difficult time warming those areas.

Warning Signs That Cold Exposure Is Becoming Dangerous

Interviewer: Okay. And I guess what I've heard before is that people don't often realize that they've got frostbite. Why is that? And what are some of the signs people should be on the lookout for?

Dr. Brant-Zawadzki: This is a great question. We've all been in the cold. If you're living in Utah, especially, we've had that numbness that sets in when things get cold. It's one of the reasons ice packs are effective for pain control, right? The problem with frostbite is that we begin experiencing that normal numbness, which is a typical response to being in the cold. But then the tissues continue to get colder and colder, and we've already lost sensation there. So we can't tell that we've gone beyond just cold, slightly numb fingers or toes to now frozen fingers and toes that are actually experiencing damage that can sometimes be irreversible.

Interviewer: Okay. And so what sign should they be looking for? If my foot's in a boot and I can't feel that it's getting worse, what sign should I be on the lookout for?

Dr. Brant-Zawadzki: So that loss of sensation is actually a warning sign. We've all been there. And most of the time, depending on the environment, it may not be severe. But you have to understand what the conditions you're in are, just how cold it is outside, especially with wind chill. And if you're starting to experience numbness, make sure that you're aware of it, that you have a plan to limit the time that you're going to be out in the cold if you can, or to try to warm up that area.

When It's Safe to Warm Up at Home—and When It's Not

Interviewer: Now, when is it okay to, say, wait and warm up, say at home or wherever you're at? And when is frostbite serious enough that you probably should get some immediate help?

Dr. Brant-Zawadzki: So moderate to severe frostbite is definitely a get to the ER situation. For mild cases, we still want to get those evaluated. They may seem harmless, but they should still be assessed if symptoms are persistent, and if those symptoms include numbness or color change, as they're just not improving with gentle warming. It can be difficult to assess, again, how severe frostbite is.

But when you're looking at skin or tissue and you're worried about frostbite, we think about that as we can see it as a spectrum. So it generally stops with what we call frostnip. And that's that minor redness, maybe a little bit of mild blanching, meaning the skin is turning white. You've got that tingling, like your finger's asleep sensation. And that'll reverse just with quick warming and not something to worry about. But again, that's one of those first warning signs.

When frostbite becomes actual frostbite, it can be either deep or superficial. So if it's superficial, the skin really has lost color. It's probably pale. It may look kind of waxy, and it loses some of that elasticity that we generally see in healthy skin. And as you warm it up, it starts to really hurt. And a lot of us have probably experienced some degree of very superficial frostbite, where you get back in front of something warm, a heat source in the room, and your fingers and toes start to burn a little bit as they're warming up. And that's somewhere on that spectrum between frostnip and hopefully not superficial frostbite, but probably some degree of it.

When it gets really severe, that's that deep frostbite. You may have seen pictures of this from climbers on Everest, things like that, where we see some really dramatic color changes in the skin. It's either blue or white completely, but there's no pigmentation at all, and there's just no sensation in that damaged tissue. Later on, we can see really, you know, dramatic signs of tissue death, like that black, dead skin, but that usually doesn't happen in the acute phase.

Interviewer: So definitely go to the ER if you're starting to get down to that frostbite area.

Dr. Brant-Zawadzki: Yeah. So if you're out in the cold and you have been exposed for a while, you take off your boot or your glove, where you look in the mirror, and you see your skin is just a deep white or it's waxy, and you just have no sensation there at all, I would definitely get to the ER to have that assessed. Hopefully, it's either just very bad frostnip or superficial frostbite. But it can be pretty difficult to really assess in the field in the moment. So you want to get to the ER, where we can assess it and warm you up appropriately.

Safe Rewarming Tips

Interviewer: Now, you mentioned rewarming, right? And when it comes from frostnip to frostbite, are there any dangers to maybe trying to rewarm damaged skin from frostbite in different ways? What's the best way to rewarm?

Dr. Brant-Zawadzki: So we want to rewarm gradually and permanently. One of the worst things you can do is warm up that tissue and then let it cool down and freeze again. So, say you're out in the backcountry, you're skiing, and you recognize that you may be experiencing frostbite. What you don't want to do is build a fire or pour hot water or hot fluid on that and try to warm it up if there's any chance that you're not going to be able to maintain that warmed tissue all the way back to the hospital because if that tissue freezes again, you're going to experience much worse tissue damage through that freeze and thaw cycle.

So we don't want to heat that tissue up until we're confident that we're going to be able to keep it warm. And then when we do heat it up, we want to be really conscious of using really like lukewarm water and gentle heating. We don't want to use really hot surfaces or hot water, like putting a hand or foot in front of the fire, for example, because again, you don't have sensation in the area. So it's really hard to know if you're getting that tissue too hot and actually getting a thermal injury as well on top of your frozen injury.

How to Prevent Frostbite

Interviewer: And what are some steps that people can take to, say, prevent that frostbite? I mean, we know if you've got it, do very slow warming, only if you can maintain it, don't do it unevenly. But what can they do to prevent frostbite?

Dr. Brant-Zawadzki: Again, frostbite typically occurs in areas that are difficult to perfuse for the body. So it's the ends of your arms and legs and the tips of your fingers and toes. So for those areas, first and foremost want to keep them covered. So don't expose them directly to the wind, snow, or moisture. If you can keep them dry and out of the elements, that's going to be very helpful. Maintaining layering, especially along the length of that limb. So, not just having good gloves and a good vest on your body, but actually having sleeves, potentially in layers, that are going to help that circulation. It's going to help keep the tips of those fingers and toes better perfused. So wearing proper equipment, both gloves on your core but also on your sleeves and legs, is really important.

And then again, not exposing those areas to the wind. That's one reason that the kind of cheeks, the ears, the nose are also really common areas to get frostbite because they're hard to cover up, especially when we're outside recreating. So, making sure that you're conscious of keeping those areas warm and checking on them frequently for sensation and for pain. And if you do notice those things, get those areas covered up or warmed up before they get too cold.

When It's Time to Go to the Emergency Room

Interviewer: All right. So, final diagnosis, ER or not, frostbite.

Dr. Brant-Zawadzki: The most important thing for management is to get to a place where you can appropriately and safely warm that part of your body and keep it warm. So don't try to warm in the field if there's any chance that you're not going to be able to keep that part of the body warm. And if you do have any concern that you've skipped past frostnip and are experiencing frostbite, get to an ER and get evaluated, because this may take some advanced treatments. And if there's any concern that you're actually experiencing frostbite, it's really important to get to a hospital, not just for rewarming, but to get some of the advanced treatments they can offer to help prevent further tissue damage and loss.