Jack Frost Nipping at Your Toes (and more)

I often like to downplay the cold weather by describing it as "crisp," or "brisk," while my wife sometimes uses more colorful language. I'm not really a fan of colder temps, though there are some benefits, like no bugs. But, there's also the ever present risk of snow, of which I am even less of a fan.

Anyway, regardless of where you stand on the pros and cons, the reality is that the winter weather does have certain health concerns, primarily conditions like frost bite and hypothermia.

I'll get to hypothermia another time, but for this week I want to discuss frostbite.

Frost bite occurs when there is cold induced tissue damage, and this is most commonly seen on the face (nose and ears), the fingers, and/or toes.

Like many medical conditions, frost bite can be seen across a spectrum, from mild to severe.

At the mildest form, there's frostnip, which is temporary cold related pain and/or numbness--also most commonly in the fingers/toes--that resolves with rewarming. There's no real tissue damage, and thus frostnip is not technically on the frost bite spectrum.

Another, lesser seen, condition called chilblains or pernia can occur from repeated exposure to damp and cold non-freezing temperatures. With chilblains, the affected skin can become swollen, red or purple, and painful. Blisters can be seen as well. This is also a temporary injury to the tissue without long lasting damage.

Now before getting into frost bite, let's take a step back and talk about what happens when your body is cold.

If your core temperature starts to drop your body will work to protect the vital organs and to keep them warm; blood vessels in the extremities constrict to keep the warmer blood circulating centrally. It's the exact opposite of what your body does when your temperature goes up and you need to shed some of that heat.

So if your body is working to stay warm, you're at risk of frost bite. If this process continues, and the skin is exposed, damage will start at the cellular level with cold induced cell death and ice crystals forming in the tissue outside the cells. The subsequent inflammatory response leads to worsening microcirculation—decreased blood and oxygen--which damages the tissue. That cycle is worsened if the area is warmed and then frozen again (which is why people are told to not try to temporarily re-warm tissue if it's likely to freeze again).

Frost bite can be classified in a similar way as burns are classified, and that's based on the depth of the tissue injury and the extent, but even "first degree" frost bite can be serious.   

Frostbite occurs in several stages (from the Mayo Clinic):

  • Frostnip. Frostnip is a mild form of frostbite. Continued cold exposure leads to numbness in the affected area. As your skin warms, you may feel pain and tingling. Frostnip doesn't cause permanent skin damage.  
  • Superficial frostbite. Superficial frostbite causes slight changes in skin color. The skin may begin to feel warm — a sign of serious skin involvement. If you treat frostbite with rewarming at this stage, the surface of the skin may appear mottled. And you may notice stinging, burning and swelling. A fluid-filled blister may appear 12 to 36 hours after rewarming the skin.  
  • Deep (severe) frostbite. As frostbite progresses, it affects all layers of the skin as well as the tissues that lie below. The skin turns white or blue-gray and you lose all sensation of cold, pain or discomfort in the area. Joints or muscles may stop working. Large blisters form 24 to 48 hours after rewarming. The tissue turns black and hard as it dies.  

Risk factors for developing frost bite, other than the temperature, the wind chill, and inappropriate clothing include: circulatory diseases, diabetes, excessive alcohol use, smoking, previous cold injury, and exposure to vibrations in the hands and arms (think, handlebars).   

Treatment options for frostbite focus on salvaging tissue, so it’s really important to prevent this from happening in the first place.   

Keep skin covered and warm with weather appropriate hats, gloves, socks, shoes and everything else. Because of the constant flux of being hot and sweaty and cold and wet, materials that wick moisture away is super important. I personally struggle with this and will often bring an extra pair of gloves and socks to swap out if needed. And depending on the weather, temperature, and wind, I may bring additional layers to change as well.   

Frostbite can happen within minutes of exposure to extreme cold, so honestly there may be some days where binging on Netflix is a better option. If you do go outside, it’s also important to stay hydrated and keep your glucose levels up.   

If you feel like you or someone you are with is developing frostbite, the first thing to do is to get into a warm environment as soon as possible.   

The best approach to warming hands and feet is to use warm—not hot--water. The re-warming process can be painful as circulation returns.  And note, the affected areas shouldn’t be rubbed during the rewarming process. Also, as mentioned, if there’s a high likelihood of the tissue being frozen again, rewarming shouldn’t be started yet.   

Frost bite really needs to be assessed by a health care professional, so the emergency department is likely your destination after the initial rewarming. You should try to protect the affected areas as much as possible, with clean gauze, padding, a splint, or other protective coverings.  

Because I don’t think anyone wants to consider amputations, I again recommend that you focus on prevention—wear appropriate clothing, keep moving to stay warm, bring extra layers, or stay inside with a cup of your favorite beverage.   

Please remember, the information presented here, including but not limited to, text, graphics, images and other material contained on this website are for informational purposes only. No material on this site is intended to be a substitute for professional medical advice, diagnosis or treatment.