When the
temperature drops below 0ºC, blood vessels directly below the skin constrict to
protect the core body temperature. When your skin is exposed to the cold for an
extended period of time, blood flow to your hands, feet, nose, and ears can be
severely restricted. The combination of poor circulation and extreme cold can
damage the skin and underlying tissues, which is known as frostbite.
Mild
frostbite (frostnip) makes your skin look yellowish or white but it is still soft to the
touch. Your skin might turn red during the warming process, but normal colour
returns once the area is warmed.
Symptoms
of advanced frostbite:
- pins
and needles feeling followed by numbness;
- hard,
pale, and cold skin that has been exposed to the cold for too long;
- the
area may ache or throb;
- lack
of sensation; you may not feel it if someone touches you there.
Severe
frostbite can
cause permanent damage to body tissue if it is not treated immediately. Nerve
damage occurs and frostbitten skin becomes discoloured and turns black. After
some time, nerve damage becomes so severe that you lose feeling in the affected
area and blisters occur. If the skin is broken and becomes infected, gangrene
can set in which can result in loss of limbs.
Frostbite may affect any part of the body. The hands,
feet, nose, and ears are the most vulnerable.
- If
the frostbite did not affect your blood vessels, a complete recovery is
possible.
- If
the frostbite affected the blood vessels, the damage is permanent.
Gangrene may occur. This may require removal of the affected part
(amputation).
First Aid for the Person Bitten by frost bite:
Mild
frostbite (frostnip) can
be treated in two ways:
Passive
warming:
·
Shelter
the person from the cold and move him or her to a warmer place. Remove any
constricting jewellery and wet clothing.
Wrap the person in blankets or reheat by skin-to-skin contact with
another person.
·
If
immediate medical help is available, it is usually best to wrap the affected
areas in sterile dressings (remember to separate affected fingers and toes) and
transport the person to an emergency department for further care.
Active
warming:
·
This can
be done along with passive warming. Soak the affected areas in warm (never hot)
water -- or repeatedly apply warm cloths to affected ears, nose, or cheeks --
for 20 to 30 minutes. The recommended water temperature is just above body
temperature (40- 42 °C). Keep circulating the water to aid the warming process.
Severe burning pain, swelling, and color changes may occur during warming.
Warming is complete when the skin is soft and sensation returns.
Once the
area is thawed:
·
Apply
dry, sterile dressings to the frostbitten areas. Put dressings between frostbitten
fingers or toes to keep them separated.
·
Move
thawed areas as little as possible.
·
Refreezing
of thawed extremities can cause more severe damage. Prevent refreezing by
wrapping the thawed areas and keeping the person warm. If protection from
refreezing cannot be guaranteed, it may be better to delay the initial
rewarming process until a warm, safe location is reached.
·
If the
frostbite is extensive, give warm drinks to the person in order to replace lost
fluids.
Severe
frostbite requires
immediate medical attention. While you are waiting for help to arrive begin
treating it with passive and active warming.
What not
to do:
- Do
NOT thaw out a frostbitten area if it cannot be kept thawed. Refreezing
may make tissue damage even worse.
- Do
NOT use direct dry heat (such as a radiator, campfire, heating pad, or
hair dryer) to thaw the frostbitten areas. Direct heat can burn the
tissues that are already damaged.
- Do
NOT rub or massage the affected area.
- Do
NOT disturb blisters on frostbitten skin.
- Do
NOT smoke or drink alcoholic beverages during recovery as both can
interfere with blood circulation.
When to
Contact a Medical Professional
Call your
doctor or nurse if:
- you
had severe frostbite;
- normal
feeling and color do not return promptly after home treatment for mild
frostbite;
- frostbite
has occurred recently and new symptoms develop, such as fever,
general ill-feeling, skin discoloration, or drainage from the
affected body part.
Prevention
Be aware
of factors that can contribute to frostbite, such as extreme cold, wet clothes,
high winds, and poor circulation. Poor circulation can be caused by tight
clothing or boots, cramped positions, fatigue, certain medications, or diseases
that affect the blood vessels, such as diabetes.
If you
expect to be exposed to the cold for a long period of time, don't drink alcohol
or smoke. Consuming alcohol before you go out in the
cold may increase your risk of hypothermia because it increases blood flow to
the extremities of the body. You may actually feel warm even though you are losing
heat. Smoking constricts your blood
vessels, impairing blood circulation.
Wear
suitable clothing in cold temperatures and protect exposed areas. In cold
weather, wear mittens (not gloves); wind-proof, water-resistant, layered
clothing; two pairs of socks; and a hat to avoid heat loss through the
scalp. Wearing a scarf that covers the
ears and nose is also recommended. Synthetic
and wool fabrics provide better insulation. Some
synthetic fabrics are designed to keep perspiration away from your body which
keep you dry and further reduce your risk.
If you get wet, change into dry clothing as soon as possible. You lose
heat faster when you're wet.
When
wearing layers of clothing, remove layers if you get too warm (before you start
sweating) or add a layer if you get cold.
If caught
in a severe snowstorm, find shelter early or increase physical activity to
maintain body warmth.
Cherie deBoer is a Registered Nurse at the Leduc Beaumont Devon Primary Care Network.
References;
Health Canada. (2013). It’s your
Health: Extreme Cold. Accessed Nov 29, 2013 @ http://www.hc-sc.gc.ca/hl-vs/iyh-vsv/environ/cold-extreme-froid-eng.php
Heller, Jacob. (2012). Frostbite. Accessed Nov 28,
2013 @ http://www.nlm.nih.gov/medlineplus/ency/article/000057.htm
