Frostbite is an injury to the body that is caused by freezing. It most often affects the nose, ears, cheeks, chin, fingers, or toes. Frostbite can permanently damage the body, and severe cases can lead to amputation.

If you have frostbite, the skin in that area may turn white or grayish-yellow. It may feel firm or waxy when you touch it. The area will also feel numb.

If you have symptoms of frostbite, seek medical care. But if immediate medical care isn't available, here are steps to take:

• Get into a warm room as soon as possible.
• If possible, do not walk on frostbitten feet or toes. Walking increases the damage.
• Put the affected area in warm - not hot - water.
• You can also warm the affected area using body heat. For example, use your armpit to warm frostbitten fingers.
• Don't rub the frostbitten area with snow or massage it at all. This can cause more damage.
• Don't use a heating pad, heat lamp, or the heat of a stove, fireplace, or radiator for warming. Since frostbite makes an area numb, you could burn it.

Frostbite is a type of injury caused by freezing. It leads to a loss of feeling and color in the areas it affects, usually extremities such as the nose, ears, cheeks, chin, fingers, and toes. Frostbite can permanently damage the body, and severe cases can lead to amputation (removing the affected body part).

The integumentary system helps regulate body temperature through its tight association with the sympathetic nervous system, the division of the nervous system involved in our fight-or-flight responses. The sympathetic nervous system is continuously monitoring body temperature and initiating appropriate motor responses. Recall that sweat glands, accessory structures to the skin, secrete water, salt, and other substances to cool the body when it becomes warm. Even when the body does not appear to be noticeably sweating, approximately 500 mL of sweat (insensible perspiration) are secreted a day. If the body becomes excessively warm due to high temperatures, vigorous activity (images a,c), or a combination of the two, sweat glands will be stimulated by the sympathetic nervous system to produce large amounts of sweat, as much as 0.7 to 1.5 L per hour for an active person. When the sweat evaporates from the skin surface, the body is cooled as body heat is dissipated.

In addition to sweating, arterioles in the dermis dilate so that excess heat carried by the blood can dissipate through the skin and into the surrounding environment (image b). This accounts for the skin redness that many people experience when exercising.

When body temperatures drop, the arterioles constrict to minimize heat loss, particularly in the ends of the digits and tip of the nose. This reduced circulation can result in the skin taking on a whitish hue. Although the temperature of the skin drops as a result, passive heat loss is prevented, and internal organs and structures remain warm. If the temperature of the skin drops too much (such as environmental temperatures below freezing), the conservation of body core heat can result in the skin actually freezing, a condition called frostbite.

You may have a greater chance of developing frostbite if you

• have poor blood circulation
• are not properly dressed for extremely cold temperatures

Frostbite occurs when temperatures get cold enough that flesh begins freezing. Though frostbite can occur anywhere on the body, it typically affects exposed areas like the nose, ears, cheeks, chin, fingers, and toes. During early stages, you’ll likely feel pins and needles in the affected areas, which will turn white. True frostbite causes the skin to appear waxy, hard, and cold to the touch.  

If you notice redness or pain in any skin area, get out of the cold or protect any exposed skin—frostbite may be beginning. Any of the following signs may point to frostbite:

• A white or grayish-yellow skin area
• Skin that feels unusually firm or waxy
• Numbness

A person who has frostbite may not know they have it until someone else points it out because the frozen parts of their body are numb.

If you notice signs of frostbite on yourself or someone else, seek medical care. Check to see if the person is also showing signs of hypothermia. Hypothermia is a more serious condition and requires emergency medical care.

If (1) a person shows signs of frostbite, but no signs of hypothermia and (2) immediate medical care is not available, do the following:

• Get the person into a warm room as soon as possible.
• Unless absolutely necessary, do not walk on feet or toes that show signs of frostbite—this increases the damage.
• Do not rub the frostbitten area with snow or massage it at all. This can cause more damage.
• Put the areas affected by frostbite in warm—not hot—water (the temperature should be comfortable to the touch for unaffected parts of the body).
• If warm water is not available, warm the affected area using body heat. For example, you can use the heat of an armpit to warm frostbitten fingers.
• Do not use a heating pad, heat lamp, or the heat of a stove, fireplace, or radiator for warming. Affected areas are numb and can easily burn.

Don’t substitute these steps for proper medical care. Frostbite should be checked by a health care provider. And remember, Hypothermia is a medical emergency and immediate medical care is necessary.

To avoid hypothermia or frostbite when going outside: 

• Dress in layers 
• Wear warm clothing to protect your hands, feet, neck and face 
• Get plenty of food and fluids 
• Avoid alcoholic drinks 

To prepare your car for a cold-weather emergency 

Make sure to have an emergency car kit with supplies like: 

• Extra warm clothing and blankets  
• An ice scraper 
• A snow shovel 
• Cat litter or sand to help tires grip on snow and ice 
• Water and non-perishable food 
• Jumper cables 
• First aid kit with any necessary medicines and a pocketknife 
• A battery-powered radio, a flashlight, and extra batteries 
• Emergency flares or distress flags 
• Waterproof matches and a can to melt snow for water 

To prepare your home for a cold-weather emergency 

Make a disaster plan and prep your home for any winter weather by doing the following: 

• Make sure you have important phone numbers – such as for your doctor and pharmacy – written down 
• Prepare your home to keep out the cold with insulation, caulking, and weather stripping 
• Gather supplies in case you need to stay home for several days without power 
• If you plan to use your fireplace or wood stove for emergency heating, have your chimney or flue inspected each year 

Taking a first aid or emergency resuscitation (CPR) course is a good way to prepare for health problems related to cold weather. Knowing what to do is an important part of protecting your health and the health of others.

Being prepared is your best defense against having to deal with extremely cold weather. By preparing your home and car ahead of winter storms or other winter emergencies, and by taking safety precautions during extremely cold weather, you can reduce your risk of developing health problems related to cold weather.