What causes frostbite?
If the air outside is below freezing, then you're at risk for frostbite. We protect ourselves by putting on boots and gloves — that's how we're able to go skiing and do other things in below-freezing temperatures. But if you walk outside and it's below freezing and you don't have shoes on, you don't have socks on, depending on your time exposure and the temperature, that can lead to frostbite. It's much quicker if you're in contact with cold water, snow, or cold surfaces, because the heat loss is much quicker when you're in contact with a cold surface than if you're just in cold air.
Are there similarities between frostbite and burn injuries?
Frostbite is a thermal injury, but it's a cold thermal injury rather than a hot thermal injury. And frostbite is different from burns, because the degree of tissue damage can be much more significant. If surgery is needed to manage the injury, it's often amputation that's required, rather than skin grafting. For burns, the injury is on the skin and however deep the burn goes. But for frostbite, the tissue damage is much deeper, because the thermal injury goes deeper. The blood vessels are clotted off, so you have no blood flow, and the tissue dies.
Are there other treatments for frostbite, before it gets to the point of needing surgery?
If a patient is referred to us early on, meaning they've had their frostbite injury and they were rewarmed within the previous 24 hours, the treatment for that is TPA therapy, which is a thrombolytic agent that busts up blood clots. Clots will form in the blood vessels during frostbite, so we then we give TPA to try to bust those clots up to reopen the blood flow to the tissue.
When people come into the burn center with frostbite, how do you go about diagnosing and treating them?
It’s different from one center to another, but the way that we do it is patients are rapidly rewarmed. If they're a candidate, they'll get thrombolytic therapy with TPA, and then we will do bone scans to see if there is blood flow to the tips of the fingers, the tips of the toes. We do an initial bone scan when they come in, then we do a second bone scan seven to 10 days later to see if there's any improvement in the blood flow.
During that time, we're doing wound care, we're assessing for color change to see if tissue goes from being purple and cyanotic to pink and little perfused at the tips. Then, based off of that second bone scan, we will start planning surgical treatment. There are many places in the United States where they take a very conservative approach and say, “We won't operate on any frostbite patients for two or three months.” They'll do two or three months of wound care, let everything fully demarcate until they can say, “blood flow is up to this point on the finger, and everything above that’s turned black is dead.” Only at that point, once they've got a clear cutoff point, will they take them to surgery.
That approach is difficult for many patients. Especially if your patient is homeless, or they have substance-use disorder, it can be very difficult for them to do their wound care on a daily basis, let alone care for themselves in other ways. Using our bone scans, we try to determine if a patient will need surgery sooner rather than later, so that we can get them moving along on their treatment.
Are there symptoms or warning signs of frostbite to watch out for if you are out in cold temperatures?
If you start having numbness in your fingers or your toes, or a burning sensation, those are typically the beginning signs of frostbite. If you see discoloration — your fingertips are turning blue or purple or pale white and they no longer blanch when you push on them — those are signs of frostbite injury.
What should you do if you start having symptoms of frostbite?
The most important thing to do is to get out of the cold and rapidly rewarm your fingers and toes. Put them in warm water, replenish that warm water a few times, and warm them for 30 minutes. If a patient is in the ED, we have constantly circulating water to keep that temperature the same, around 104 degrees Fahrenheit. But if you're at home, you have to refill and keep the water warm; otherwise, the temperature is going to drop and become more like room temperature by the time you're done.
At what point should you seek medical help?
You should seek medical help if the tips of your fingers or your toes turn purple, especially after rewarming, or if they're still numb after rewarming. Typically, if you get frostbit, it's going to be quite painful as you rewarm. The fingers or the toes will swell from increased blood flow to the area, and that can be quite painful. In those situations, taking over-the-counter pain medications is important. Often people will take their fingers or toes out of the water and stop rewarming because of the pain. But the pain is actually a good thing. It's a sign that the blood flow is returning. It's really important to do that 30 minutes of active rewarming, not passive. And don't put your feet or your hands close to heaters or the fireplace, because you might end up burning yourself.
What's the best way to prevent frostbite from happening?
Wear warm, dry clothes and avoid being outside when temperatures are dangerously low. When it's 30 degrees Fahrenheit, you can be outside for quite some time before you develop frostbite. If it's negative 10, negative 20 degrees Fahrenheit, you can develop frostbite extremely quickly. If your gloves or your shoes get wet, get somewhere warm, take them off, and start rewarming. Don't stay outside, because if your shoes get wet, your gloves get wet, they are going to freeze, and that's going to be even worse than if your hands were out in just cold air.