Winter's chill can seem like a mere annoyance, at first.
But human skin can stiffen and blister when subjected to freezing temperatures like those endured by the Chicago area this week. Worse, prolonged exposure can cause a dangerous and potentially fatal drop in the body's core temperature.
While area hospitals reported only a few recent frostbite cases Monday, area health experts still urge caution in the cold.
Commuters or shovelers who dawdle outdoors with exposed skin risk contracting a mild case of frostbite — tissue frozen by poor circulation and frigid temperatures.
But residents, particularly infants and the elderly, can develop hypothermia if subjected to cold temperatures for prolonged periods. City health officials said that separate condition, marked by a drop in body temperature, contributed to the deaths of six people in Chicago from October through late December.
People with frostbite first begin to lose feeling in their skin, said Dr. Bechara Choucair, head of Chicago's public health department.
Affected tissues often turn white or gray, and begin to feel unusually firm or waxy. Blisters and more severe skin discoloration can begin to develop later, Choucair said, requiring more advanced medical care. The body parts most vulnerable to frostbite in these conditions are the nose, ears, cheeks, chin, fingers and toes, he said.
"So you'll want to make sure those are protected," he said.
In temperatures like this week's, doctors add that people can start developing the beginning symptoms of frostbite — known as frostnip — in 5 to 10 minutes.
Choucair said lukewarm water can be used to treat mildly frostbitten areas, but hot water and electric blankets should be avoided. Frostbitten skin also shouldn't be rubbed or exposed to friction.
By contrast, experts said hypothermia's separate and severe effects can't be treated with home remedies.
As the body's temperature cools below normal, hypothermia victims often begin to feel forgetful or drowsy; heartbeats slow, pulses weaken and breathing can become shallow. Eventually, the body stops shivering.
"It doesn't mean the patient is getting better," said Dr. Kimbra Bell, a professor at Northwestern University's Feinberg School of Medicine. "Shivering is actually a good sign because it indicates a person's heat regulation systems are still active."
"When it comes to hypothermia, you have to think about individuals who are homeless and mentally ill, or those who could very well be in situations of prolonged exposure because of that," Bell said, as opposed to a shoveler without proper gloves.
Infants can also be at higher risk because they lose body heat more quickly than adults, Bell and the health department said, while elderly patients often create less body heat because of slower metabolisms and reduced physical activity.
"The key here is to seek medical attention," he said.
