So, you’ve been out in the cold, and now your fingers or toes are all weird and painful. Is this frostbite? Are you doomed to suffer the fate of so many ill-fated Victorian polar explorers, your extremities lost to the bitter wind and snow? Or did you just sit too close to the radiator, and give yourself chilblains?
It’s easy to see where the confusion between chilblains (also known as pernio) and frostbite comes from: after all, they are both brought on by exposure to the cold. But in fact, the two conditions have quite a few differences – from how and why they set in, to how they’re treated, and even how they might affect you years down the line.
What causes chilblains and frostbite?
Both chilblains and frostbite are the result of being out in the cold for too long. But there’s actually a big difference in why, exactly, each condition occurs – at least, we think.
Frostbite, for example, sets in when exposure to cold temperatures causes the blood vessels to constrict, reducing blood flow to the body’s extremities. This is good news for your vital organs – frostbite is, after all, your body trying to keep you alive – but it means that less important areas like your hands, feet, ears, nose, and lips will be starved of oxygen.
Stay too cold for too long, and this lack of blood flow also means the tissue in those areas can literally freeze. You know how humans are 60 percent water? Well, when it gets too cold, water turns to ice – and at temperatures below about -23°C (-9°F), that’s exactly what starts happening to the cells inside your body, too.
“Frostbite begins with mild symptoms but quickly becomes a serious health risk the longer your skin freezes from exposure,” explains the Cleveland Clinic. “There are three stages of frostbite… in the second stage, your skin might feel warm, but the water in your skin is slowly freezing into ice crystals.”
Chilblains, on the other hand – well, nobody’s entirely sure what causes that. Sometimes they’re not even caused by cold: the condition has been linked to other diseases like lupus, erythromelalgia, and lately – though certainly not undisputedly – to COVID-19.
The leading theory, though, is that it’s not actually a reaction to the cold, but to warming up: “Rewarming of cold skin can cause small blood vessels under the skin to expand more quickly than nearby larger blood vessels can handle,” suggests the Mayo Clinic. “This results in a bottleneck effect and the blood leaking into nearby tissues.”
What are the symptoms of chilblains vs frostbite?
So how do you tell the difference between the two conditions? Well, the first question you might want to ask yourself is: how long is it since you were in the cold? If you’re still in sub-zero temperatures, that’s a pretty big clue you’re dealing with frostbite rather than chilblains – the latter condition usually doesn’t manifest until a few hours after you get out of the cold.
But what else separates the two conditions? There’s the physical sensations: one of the earliest symptoms of frostbite is numbness following pins and needles in the affected area, and the skin will feel very cold. This mild form of frostbite – or at least, as mild as frostbite gets – is called frostnip, and it’s not as rare as you might think. It’s more of an irritation to the skin than deep tissue damage, and so long as it’s treated before it gets worse, you may never even need to see a doctor about it.
If exposure to the cold continues, though, and the frostbite gets worse, the increased tissue damage will start to make first your skin, and then the underlying tissues including even muscle and tendons, feel hard and frozen. Your skin may, paradoxically, start to feel warmer – that’s not a good sign: it means you’re starting to see some very serious skin involvement.
Chilblains, on the other hand, are marked by feeling itchy, or possibly like a burning sensation. Rather than feeling hard to the touch, chilblains can make your extremities swell up, and cause blisters or even ulceration on the skin.
With later-stage frostbite, it’s easier to see the differences from chilblains. Rather than turning red, or even dark blue, as with chilblains, advanced frostbite can turn your tissue white or grey as the cold progresses further and further into your body. Past that, you can expect your extremities to turn black as tissues die, and eventually, they may even auto-amputate – that’s a medical euphemism meaning “drop off”, by the way.
In its milder stages, though, it’s easy to see why the two conditions can get confused for one another. In fact, milder frostbite can actually lead to chilblains as it heals.
Luckily, at that early stage, the treatment for both is basically the same – but if deeper frostbite sets in, that situation changes drastically.
How do you treat chilblains and frostbite?
The biggest difference between the two conditions really comes in their treatment. The good news: chilblains, at least, tend to go away on their own within a few weeks.
“Chilblains usually clear up within one to three weeks, especially if the weather gets warmer,” explains the Mayo Clinic. “You may have recurrences seasonally for years… [but] chilblains don't usually result in permanent injury.”
In fact, the best “treatment” for chilblains is just … to not get them in the first place. “The best approach to chilblains is to avoid developing them,” the Mayo Clinic advises, “by limiting your exposure to cold, dressing warmly and covering exposed skin.”
Frostbite, on the other hand, requires some pretty specialized aftercare. Even just to evaluate how severe the condition is may need X-rays or MRI scans – and if it’s progressed to an advanced stage, you can forget treating it at home with just a warm blanket and hope.
“Mild frostbite… can be treated at home with first-aid care,” the Mayo Clinic advises. “For all other frostbite, after appropriate first aid and assessment for hypothermia, medical treatment may involve rewarming, medications, wound care, surgery and various therapies, depending on the severity of the injury.”
Those treatments can be as simple as a warm bath and painkillers, or as invasive as amputation of dead or dying tissue. Sometimes, specialist equipment like whirlpool baths or hyperbaric oxygen chambers might be used, along with aggressive drug treatments to avoid blood clots.
The worst part? Frostbite can continue to affect you even years down the line. “People with a history of severe frostbite often report further long-term effects,” notes the UK’s NHS article on the condition. “These can include: increased sensitivity to cold; numbness in the affected body parts, most commonly the fingers; reduced sense of touch in the affected body parts; [and] persistent pain in the affected body parts.”
While chilblains and frostbite have some similarities, they’re actually very different conditions – especially when it comes to treatment and long-term effects. Our advice? Try to avoid both: wrap up warm in layers; keep dry, even from your own sweat; and avoid alcohol and drugs that may impair your body’s natural responses to the cold.
And remember: you’re not the only one who can get frostbite. Pets and young children are especially prone to the condition, but usually either can’t tell us or don’t realize what’s going on until the condition has already set in. So, as well as looking out for yourself this winter, keep an eye out for your loved ones too. Nobody wants an amputated toe for Christmas.