On a bitterly cold Canadian winter morning, there may be nothing better than turning on the heated seats and letting your bum warm up as you drive to work.
But there is a new warning out about using this cozy vehicle feature too much after two women burned their bums on normally-functioning heated seats.
A recent article in the Archives of Dermatology presents cases where the seats cause erythema ab igne (toasted skin syndrome). It's a condition that leaves lesions on one's backside and causes pain, itchiness and more.
The two women mentioned in the cases are a 40-year-old who used her heated seat an hour a day during Ohio's four-month winter season and a 67-year-old who drove 120 hours with the seats activated.
"I've seen plenty of cases of erythema ab igne over the years, but this is the only case I've seen that's stemmed from a heated car seat," said Dr. Eliot Mostow, an Ohio dermatologist, who wrote about the case involving the 40-year-old woman, in an MSNBC Body Odd blog. "Most cases I've seen have been from heating pads. People use them for back pain for a few months and do it every night. It's a combination of duration and repeated use, long-term use."
Heated car seats can reach temperatures of 43 degrees Celsius and repeated exposure to moderate head can cause pigment change.
"It's probably related to some blood vessel changes and changes in the pigment cells," says Mostow. "You get more severe cases with longer exposure, But to be honest, everybody's different. Some people will get it sooner with the exact same exposure."
For the younger of the two women, her skin colour changed back and her itching went away after she stopped using the heated seat.
The older woman had rusty brown patches on the backs of both legs, but the right leg has less presumably because she would pick it up more to step on the gas and brake pedals. Mostow suspects she will have permanent colour change.
This Canadian winter has been warmer than usual, but if people are going to use heated seats Mostow suggests using them in moderation. He tells the Body Odd, "If I had a recommendation, it would be to use the car seat heater to warm up the seat, then turn it off. When it gets cold, turn it on again. But don't use it for a whole six-hour drive."