Frostbite is quite common. We cannot estimate how many cases of frostbite there are annually because it frequently doesn’t cause lasting soft tissue damage or merit medical attention. But severe cases of frostbite are quite serious. If it is allowed to continue progressing, frostbite can become extensive enough to cause gangrene – death of body tissue resulting from absence of blood flow, which can become fatal unless the affected limb or area is amputated.

In this article we will explain what frostbite and its three stages are, as well as the seven warning signs that you may have frostbite. It is important to recognize frostbite at its earliest stages, as doing so can help you avoid severe injury and discomfort!


What Is Frostbite?

The human body is mostly water (about 60% for men; about 55% for women). Water freezes when it is chilled to 32 °F or cooler, although body tissue will freeze when it is consistently exposed to a temperature of or below 28 °F.

Water expands when it freezes. When the water inside a cell expands, the thin membrane surrounding the cell can no longer contain its contents. The cell dies when it ruptures, which is why cryopreservation is impossible with current medical technology.

Frostbite occurs when the skin – and possibly the soft tissue beneath it – freezes. In the simplest possible terms, frostbite kills whichever parts of your body it affects. In fact, the damage frostbite inflicts to soft tissue isn’t all that much different from blunt force trauma.

Frostbite most commonly affects the extremities of the body. This is partly because the body restricts blood flow to the ears, nose, cheeks, chin, fingers and toes in favor of the vital organs when it is cold outside. Frostbite also affects extremities first because they are typically exposed to cold air, and have greater surface area from which to lose warmth.

We mentioned earlier that most cases of frostbite aren’t dangerous. This is because the condition is progressive. It occurs in three stages, beginning with the least severe:

  • Frostnip – The mildest form of frostbite, which is accompanied by zero permanent skin damage. The affected area feels numb while it is cold, and may tingle or become painful as it warms up.
  • Superficial frostbite – The intermediate form of frostbite. The skin may change to red, white or another abnormal color. Burning, swelling and stinging sensations are all common. Paradoxically, the skin may also begin to feel warm. One or more fluid-filled blisters may appear within 12 to 36 hours of rewarming the skin.
  • Deep frostbite – The skin continues to change color, but all sensation ceases in the affected area. In extreme cases the skin will turn black – evidence that permanent tissue death has occurred. Underlying joints and muscles may also stop functioning.

What Are the Warning Signs of Frostbite?

Knowing the warning signs of frostbite won’t just help you avoid intense discomfort. It can also save your irreplaceable fingers and toes! If you notice any of the following warning signs of frostbite, immediately seek shelter in a warm place. If the symptoms are severe enough, you may also require medical attention.

Cold temperatures – When it is 0 °F or colder outside, exposed skin can develop frostbite in as little as 30 minutes. When it is -15 °F or colder, frostbite can occur in half that time. Wind chill can only accelerate the onset of frostbite, so keep an eye on the thermometer and the weather forecast. The best warning sign of frostbite is the one you don’t have to physically experience.

Prickling and/or numbness – Either of these sensations could indicate a risk of more severe frostbite if the skin isn’t allowed to warm up again. It is caused when blood flow is restricted to the fingers, toes or other extremities.

Change in skin color – Your skin may turn one of a wide range of colors once its blood flow has restricted, including red, white, blue-white, gray-yellow or brown. Note that changes in skin color are less evident in darker skin. Melanin provides fantastic protection against the sun, but it does make detecting frostbite symptoms more difficult. (Unfortunately, the pigment can also obscure symptoms of skin cancer.)

Clumsiness – Without an ample supply of blood, the muscles and joints beneath the skin cease to function correctly. If you are ice fishing and notice that you are having difficulty performing delicate actions with your hands, frostbite is the most likely culprit.

Change in skin texture – Hard, shiny or waxy skin indicates the presence of superficial frostbite. At this phase it is critical to seek warm shelter, as permanent damage is still avoidable.

Blistering – Frostbitten skin will begin to blister several hours after it is allowed to warm up again. Blistering is not technically a warning sign because it presents itself after the fact, but it does provide confirmation that you avoided more serious bodily harm.

Black or purple skin – These colors typically indicate that blood hemoglobin has oxidized. In simpler terms, tissue death has occurred. The tissue will continue to decay and potentially become life-threatening if the skin or extremity isn’t amputated.


When Should You See a Doctor for Frostbite?

You should seek medical attention if you experience symptoms of superficial or deep frostbite, including change in skin color, severe blistering, hard skin and loss of joint or motor function. Before you seek medical attention, make certain to remove any wet clothing you are wearing and protect any affected areas from the cold. If you believe your feet are frostbitten, avoid walking until you have received medical care.

If you believe you have suffered frostbite on your feet, then the passionate podiatrists of Twin Cities Foot & Ankle Clinic are available to see you right away. We welcome you to contact us today to schedule a visit at our convenient location in Golden Valley, Minnesota!