Why you can burn yourself with ice: what is cold burn

If you hear someone talking about burnsyou will surely think that he got too close to the chestnuts on the fire or that he touched something glowing. I mean, burns = fire, right? No, actually even ice can make us burn, causing burns very similar to those caused by fire or very high temperatures. The fault lies in the low temperatures that lead to the formation of ice crystals inside and outside our cells and the narrowing of blood vessels, preventing blood from passing through. It can happen both slowly, as in cases of frostbite, when one is exposed to low temperatures for too long, but also in the case of contact with pressurized gases (such as propane or nitrous oxide) or with dry ice. The symptoms are similar to those of heat burns: skin that changes color, blisters, blisters and ulcerations, up to necrosis.

What happens in cells with an ice burn

When our body is subjected to extremely low temperatures, whether we are lost in the polar wilderness or enjoying the molecular cuisine and dry ice, the mechanism by which cellular damage occurs is the same. Consider that the freezing process begins between -2°C and -10°C, but a 20-second contact with a propellant gas for aerosol sprays, such as propane or butane, is enough to lower the skin temperature to -40°C.

If we freeze slowly, the water outside the cells begins to crystallize: to try to maintain the balance between inside and outside, water leaves the cells, altering the pH and the concentrations of cellular ions and solutes, which can reach levels that are toxic to the cell. These alterations, in turn, cause structural changes in membrane proteins and lipids that lose their functionality, ultimately leading to cell death.

Similarly, contact with dry ice, composed of solid carbon dioxide or pressurized gases such as propane used as a propellant in aerosol sprays or nitrous oxide, causes what are called “flash freeze“, i.e. rapid freezing. The drop in temperature, however, is much faster, to the point that the water present inside and outside the cell immediately crystallizes. The small crystals that form they literally pierce the cell membraneobviously causing the death of the unfortunate cell.

At the same time, the cold has another indirect effect: narrows blood vessels (vasoconstriction). It means less blood reaching the tissues (hypoperfusionin technical jargon), thicker blood and risk of thrombus formation.

There’s no need to rush to warm up!

To recover, a hot chocolate and a nice blanket in front of the fireplace are not enough; in fact, heating up too much too quickly could make the situation worse. They are the so-called “reperfusion damage”, which occur when blood flows back into a tischemic tissuethat is, for some time it did not receive oxygen and nutrients.

When blood flow is restored, it can cause a inflammatory reactionworsening the damage already present. Additionally, reperfusion can cause edema (swelling), thrombosis (a condition in which a clot of blood travels undisturbed in the vessels until it encounters one that is too small in which it gets stuck and blocks it without allowing more blood to pass) and hemorrhages.

In fact, the treatment of frostbite burns involves heating slowly the affected area a no higher than 40°Cuse topical creams appropriate to the wound (sometimes, for example an antibacterial cream may be necessary) and drugs to soothe the pain or thrombolytics to break up, as the term suggests, the clots. Typically, surgery or amputation is used only in the most serious cases.

What does a cold burn look like?

Like classic burns, cold burns are also classified into four degrees based on the severity of symptoms ranging from a feeling of itching and numbness, with the skin possibly changing colour, becoming yellowish or greyup to severe pain, blistering and necrosis which also extends to the underlying tissues, sometimes even to the muscle.

For simplification, a distinction is often made only between “superficial burns”, which do not affect the tissues under the skin, and “deep burns”, when the damage is very extensive and has affected other tissues in addition to the skin.

Who is most at risk of getting burned by ice?

Surely those who are most at risk of these burns are the people who work with these pressurized gases, or with cryogenic liquids, for example those used in both medical and aesthetic cryotherapy. Once at room temperature, they quickly vaporize upon contact with the skin, causing cell damage. In some cases, even just touching a container containing these gases can cause a cold burn.

You can get “burned” on ice even if you do we apply for too long directly on the skinfor example if we do not use the necessary precautions with the ice packs. Finally, even if it seems strange, there are those who dare to spray dangerous aerosols on their arms, as reported byAustralian Journal of General Practice in a 2018 review, or those who use nitrous oxide for “recreational”, causing painful skin burns, as highlighted in a recent study published inEuropean burn journal.