Introduction

Frostbite is damage to skin and tissue caused by exposure to freezing temperatures typically any temperature below minus 0.55C (31F).

Frostbite can affect any part of your body.However, the extremities, such as the hands, feet, ears, nose and lips are most likely to be affected.

The symptoms of frostbite usually begin with the affected parts feeling cold and painful. If exposure tothe cold continues, you may feel Pins and needles before the area becomes numb, as the tissues freeze.

When to seek medical attention

If you think you or someone elsemay have frostbite, call your GP or NHS 111 for advice.

If the symptoms are more severe or there are signs of hypothermia , such as constant shivering or fast breathing (hyperventilation), go immediately to your nearest accident and emergency (A&E) department .

A doctor willexamine the affected area, check your vital signsand ask howthe frostbite occurred.

In somecases, you may need a follow-up appointment or referralto a specialist, becausethe full extent of a frostbite injury is often not apparent until a few days later.

Treating frostbite

A person with frostbite should be taken to a warm environment as soon as possible. This isto limit theeffects of the injury andbecause it's also likely they'll have hypothermia . Don't putpressure on the affected area.

Thefrostbittenarea should be warmed up by a healthcare professional. This is usually done by immersing the affected area in warm (but not hot) water.A bath of water at 40-41C (104-105.8F) is recommended for re-warming. The re-warming process is often very painful and large amounts of painkillers may be needed.

It's important not to re-warm the affected area if there's a chance of it freezing again, becausethis can lead to further tissue damage.

In severe cases of frostbite, the loss of blood supply to the tissue may cause it to die ( gangrene ). Atype of surgery called debridement may be needed to remove the dead tissue. In very severe cases, amputation may be needed.

Blood flow to the extremities slows down, so that blood flow tothe vital organs can be increased.

As the blood is redirected away from the extremities, these parts of the body get colder, and fluid in the tissue can freeze into ice crystals.

The ice crystals can cause severe cell and tissue damage in the affected area. The low blood flow also deprives the tissues of oxygen. If blood flow can't be restored, the tissue will eventually die.

At-risk groups

Certain groups of people are at greater risk of getting frostbite. They include:

• people who take part in winter and high-altitude sports, such asmountaineers and skiers
• anyone stranded in extreme cold weather conditions
• anyone who works outdoors in harsh conditions for long periods of time, such as soldiers, sailors and rescue workers
• homeless people
• the very young and very old, as their bodies are less able to regulate body temperature
• people with conditions that cause blood vessel damage or circulation problems, such as diabetes and Raynaud's phenomenon
• anyone taking medication that constricts the blood vessels, including beta-blockers (smoking can also constrict the blood vessels)

Many cases of frostbite occur in people who have taken drugs or drunk alcohol . Taking drugs or being drunk can lead to risky behaviour,not responding normally to cold, or falling asleep outside in cold weather.

As you'd expect, cases of frostbite in England often rise during particularly cold winters. For example, during the very cold winter of 2010-11, there were 111 hospital admissions for frostbite. In most years,there are around 30-60 cases every winter.

Preventing frostbite

Almost all frostbite cases can be prevented by taking precautions during cold weather.

Avoid unnecessary exposure to cold temperatures.The combination of wind and cold temperatures (wind chill) can also cause a rapid drop in temperature, so avoid going out when it's cold and windy, if possible.

It's also important to know what the early symptoms of frostbite are, particularly the tingling sensation of frostnip.

Wear appropriate clothing that protects your extremities, such as:

• well-insulated boots and a thick pair of well-fitting socks
• mittens they provide better protection against very cold weather than gloves
• a warm, weatherproof hat that covers your ears it's important to protect your head from the cold
• multiple thinlayers of warm, loose-fitting clothing these act as insulation

You should also try to keep dry and remove any wet clothing as soon as you can.

If you're travelling during cold weather, plan for emergencies. For example, if you're driving in icy conditions, make sure you keep a warm blanket and some spare clothes in the boot of your car, in case you break down.

If you'retravelling by foot, always let others know where you're going and what time you'll be back. Take a fully charged mobile phone with you, so you can call for help if you have an accident, such as a fall.

Be careful when drinkingalcohol during very cold weather. Drinking too much increases your risk of falling asleep in the cold (a common cause of frostbite). Alcohol also causes you to lose heat at a faster rate.

Smoking also makes you more vulnerable to the effects of the cold, becausenicotine can narrow your blood vessels.

Complications of frostbite

If some of your tissue dies,the dead tissue will no longer have a blood supply. This can make the affected body part very vulnerable to infection, because your body relies on white blood cells to ward off infections.

Peoplewith frostbite are atrisk ofbacterial wound infections, such as tetanus . More seriously, this infection can spread into the blood ( sepsis ), which requires treatment with antibiotics . Both conditions require hospital admission.

and treating sepsis .