Doctors at Vancouver General Hospital in Canada said a 37-year-old jogger wearing an iPod was burned on his chest, neck and face after the man and a nearby tree were struck by lightning in 2005. The burns traced the path of the earphones, they said.
The patient's eardrums were ruptured and the tiny bones in his middle ears were dislocated, the doctors wrote in a letter to the New England Journal of Medicine.
The man's jawbone broke in four places and both jaw joints were dislocated, probably because the electric current made his jaw muscles contract violently, Eric Heffernan, Dr. Peter Munk and Dr. Luck Louis wrote in their letter.
The metal in the earphones helped channel the current and cause the injuries, they said.
"Although the use of a device such as an iPod may not increase the chances of being struck by lightning, in this case, the combination of sweat and metal earphones directed the current to, and through, the patient's head," they said.
Heffernan said it's not just iPod headphones that pose a risk. "I think that this has the potential to occur with any sort of headphones."
Two years later, more than half the patient's hearing is gone and he cannot hear high frequency sounds, even with hearing aids.
"He still jogs, and he bought a new iPod after the incident, but he leaves it at home now when he goes jogging," Heffernan, a radiologist, said in a telephone interview.
The National Weather Service has estimated that a person's odds of being struck by lightning are 1 in 5,000. About 10 percent of those who are struck die.
"I think the message should be that, in the event that you're jogging and get caught in a thunderstorm, make sure your iPod is not in contact with your skin and remove the earphones from your ear," Heffernan said.