Q: My kids love to play outside, even in the cold and snow. How can I protect them from frostbite?
A: Frostbite, ironically, results from the body's attempt to protect itself against the cold. Our body cares much more about the temperature of its inside self than the temperature of its outer self.
What do I mean? The normal temperature inside our body (our "core temperature") is around 98.6 F. The organs inside -- the brain, heart, lungs, liver, kidneys and others -- function best at that temperature. When our whole body is exposed to very cold air, it's our outer organs that start to cool off first.
When cold blood in the skin returns to the inside of the body, it threatens to lower the core temperature.
To fight against that, when our skin gets very cold the blood vessels in and near the skin start to narrow. As a result, less cold is carried to our insides, protecting our core body temperature. But protecting the core temperature by reducing blood flow to the outer part of our body can go too far. If the blood vessels in and near the skin clamp down too much, this can cause dangerously low blood flow, particularly in our toes, fingers, ears and nose.
The combination of cold temperature and poor blood flow can cause frostbite: the freezing of skin, muscle and even bone.
If your children insist on playing outside in the cold, you can protect them in several ways:
• Dress them in loose layers. The outermost layer should be wind-resistant to reduce heat loss. Inner layers of silk, polypropylene or wool will keep them warmer than cotton.
• Keep them dry. Remove wet layers or dress them in layers that wick moisture away from their skin. If their skin gets wet, it loses heat more easily.
• Be vigilant. Check periodically for signs of frostbite. Your children may not feel your touch on their fingers or toes. Their skin may look waxy, white or lighter than usual, or it may appear pink or red. It may feel overly soft. As frostbite worsens, the skin may become hard.
• If they start to shiver, have them go inside. If your children do end up with mild frostbite, gently blow air on the affected area, or place it against a warmer area of the body. For example, place their fingers in between your hands.
If they experience serious frostbite, go to an emergency room as soon as you can. It's best to warm frostbitten areas under medical supervision, as some attempts to treat frostbite can actually cause damage.
To protect against damage, do not use massage, water warmer than 110 degrees Fahrenheit, or dry heat, such as a radiator or hair dryer, to warm the body part.
Mild frostbite usually heals well without complications. More severe frostbite may cause permanent tissue damage.
So be watchful about frostbite. And hope for an early spring!
• Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com.