FROSTBITE By Mark B. Levin, M.D., Louis J. Tesoro, M.D. and Timothy J. Patrick-Miller, M.D. The Pediatric Group, P.A., Princeton

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Now that winter is here and we in the East have experienced our first big snowstorm of the year, the kids are chomping at the bit to go outside to sled and play in the now. Parents, of course, are not so eager to carry out their snow-related responsibilities (shoveling). In either case, our skin is vulnerable to the very cold weather associated with the snowfall. If not properly prepared, any of us can suffer frostbite.

The mechanism of frostbite is akin to a heat injury in terms of the process the skin undergoes and can be just as debilitating. When the skin is exposed to low effective temperature of the ambient air, the skin first becomes reddened. The most susceptible areas are the fingers, toes, nose, ears and cheeks. All of us have certainly experienced this stage of cold exposure and have witnessed full recovery on simple re-warming of the skin. This stage is not usually associated with significant discomfort.

On continued cold exposure, the skin next turns white. At this stage, there is usually some associated pain. People with a darker complexion may have less apparent color change and should be particularly careful in this environment. When this stage of frostbite is encountered, immediate re-warming is mandatory. Re-warming should be accomplished with warm water (not hot or cold) to apply an even, gradual and constant temperature to the skin. Because the nerves are also injured, this can be painful. Analgesic medication, such as ibuprofen or acetaminophen can be administered to help alleviate the pain. As with heat-related thermal injury, the surface area of the injured skin is an important consideration. Injured skin tends to sequester fluid. If the affected surface area is greater than the size of two palms of the hands, medical intervention should be sought. If the affected individual must replace the fluids by increasing oral intake, otherwise low blood pressure can result.

The last stage, skin death, is critical to avoid. In this stage, the pain subsides and the skin takes on a gray, brown or black appearance. Immediate medical intervention, which may include skin grafting for larger areas, is necessary. As in the blanching stage, people with a dark complexion need to be more vigilant of associated symptoms. Although continuous cold exposure is dangerous, skin recently damaged from frostbite will be even more susceptible to subsequent cold weather exposure.

Whenever weather forecasters talk about cold weather they frequently mention the "wind-chill" factor. A breeze cools the skin by a process termed convection. That is why we fan ourselves in hot weather, even though fanning does not change the air temperature. Heat loss caused by a breeze adds to the cooling caused by the cold air temperature. Consequently, in the presence of a breeze, skin damage is greater than at the same temperature without a breeze. The chart below shows approximate wind chill values for various temperatures in the presence of increasing wind velocity and risk of exposure. Keep in mind that people with sensitive skin, especially the elderly, the very young and those with underlying skin inflammatory disorders, are at even greater risk than those without these factors.

Like wind, wetness cools the skin, but by an alternate physical process called evaporation. This is why we douse our heads with water in hot weather (when other more socially acceptable means of cooling are not available!). For water to evaporate, it must absorb heat from the body surface on which it resides. If a person outside in cold weather experiences wetness in their gloves or boots, whether it is from inadvertent snow inoculation or from perspiration, that water will cool the skin as it evaporates. When evaporation is added to the cold temperature outside, the skin behaves as if it were exposed to temperatures much colder than the ambient temperature.

All of this makes winter sound like an unnaturally dangerous time of year. To the contrary, winter can be a joyful season full of exciting experiences if they are practiced safely. A native Alaskan tour guide once responded when asked if the temperature became too cold during the winter in Alaska, "There is no such thing as cold weather; only inappropriate dress." The message here is that preparation and precautions should allow us all to have fun in the snow without undue hardship as long as we dress properly in layers (covering all exposed skin), limit our time outdoors, drink plenty of warm liquids and have shelter available when we need it. Have fun!

Dr. Mark B. Levin 

Dr. Levin has been a member of the staff at The Pediatric Group since 1977. Currently an attending Pediatrician at the Medical Center at Princeton, he has been Chairman, Department of Pediatrics, Medical Center at Princeton, 1984 to 1986, 1989 to 1992, and past President, Medical and Dental Staff, Medical Center at Princeton, 1987 to 1988. Dr. Levin has served on numerous Departmental and hospital committees. He has published original articles both while at Upstate Medical Center in Syracuse and at The Pediatric Group. He has a wife and three children. Dr. Levin enjoys alpine skiing, jogging, hiking and camping, travel, computers and racquetball.

Dr. Louis J. Tesoro

Dr. Tesoro has been a member of the staff at The Pediatric Group since 1988. Dr. Tesoro is Attending Pediatrician, Medical Center at Princeton, 1988 to present. He has served on several Departmental and hospital committees and was Chairman, Department of Pediatrics, Medical Center at Princeton from 1996 - 2000. He has lectured at the Universiy of Pennsylvania and has published original articles both while at The Children's Hospital of Philadelphia and at The Pediatric Group.

Dr. Timothy Patrick-Miller Dr. Patrick-Miller has been a member of the staff at The Pediatric Group since 1985. Dr. Patrick-Miller has served on several Departmental and hospital committees. He has published original work while at The Pediatric Group. He and his wife enjoy travel. He also likes hiking, biking, gardening and reading.

ŠAll rights reserved, The Pediatric Group, P.A. 2005