A variety of frostbite classification systems have been proposed. The easiest to understand, and perhaps the one that gives the best clues to outcome, divides frostbite into 2 main divisions: superficial and deep.
- In superficial frostbite, you may experience burning, numbness, tingling, itching, or cold sensations in the affected areas. The regions appear white and frozen, but if you press on them, they retain some resistance.
- In deep frostbite, there is an initial decrease in sensation that is eventually completely lost. Swelling and blood-filled blisters are noted over white or yellowish skin that looks waxy and turns a purplish blue as it rewarms. The area is hard, has no resistance when pressed on, and may even appear blackened and dead.
- You will experience significant pain as the areas are rewarmed and blood flow reestablished. A dull continuous ache transforms into a throbbing sensation in 2-3 days. This may last weeks to months until final tissue separation is complete.
- At first the areas may appear deceptively healthy. Most people do not arrive at the doctor with frozen, dead tissue. Only time can reveal the final amount of tissue damage.
When to Seek Medical Care
A doctor must be able to see and feel the affected area. A simple telephone call is probably not sufficient in all but the mildest cases of cold injury to hands and feet. You need to see a doctor for care.
At the time of initial evaluation, it is very difficult to categorize the injury as superficial or deep, and even more difficult to ascertain the amount of tissue damage. Therefore, all people should be seen by a doctor, who will supervise the rewarming process, attempt to classify the injury, and further guide the treatment process. Someone with frostbite will need evaluation for, and possible treatment of, hypothermia and dehydration.
Exams and Tests
The doctor will take a history in order to gather information on the events of the exposure and the medical condition prior to the cold injury.
- The doctor will take note of the vital signs, including temperature, pulse, blood pressure, and respiratory rate in order to exclude or treat any immediate life threats such as hypothermia or severe infection.
- X-rays may be performed, but they probably will be deferred until weeks later when they are more useful to the treatment team.
- The doctor will collect data in order to classify the injury as superficial or deep and the prognosis as favorable or poor.
- A good prognosis is heralded by intact sensation, normal skin color, blisters with clear fluid, the ability to deform the skin with pressure, and the skin becoming pink when thawed.
- Blisters with dark fluid, skin turning dark blue when thawed, and an inability to indent the skin with pressure indicate a poor prognosis.