The maker of a popular activity-tracking device is apologizing to customers who have had bad reactions from wearing it.
People from all over the country have reported skin irritations from wearing the Fitbit Force.
The device works as a combination watch, pedometer and sleep tracker.
The reactions customers have had look like bad rashes or even burns.
"The problems in some cases have been quite severe and require prescription-strength creams or even prescription-strength oral medications to help clear up and resolve," said Jennifer Lee, medical director at REN Dermatology.
Lee said some people may be allergic to the nickel in the bands.
"People were noticing the rash at the wrist where they were wearing the Fitbit," said Lee. "They would try to change it to the other wrist and they would break out there as well, demonstrating that they became sensitized or allergic to whatever's in the material."
Nickel is one of the most common things people can become allergic.
"People develop reactions to earrings. People develop reactions to the metal belt buckle or the button of their jeans and we never think to complain to the manufacturer of those materials," said Lee. "I think it's interesting people are having such severe reactions, but it's hard to know how much to blame the manufacturer of Fitbit."
The maker of Fitbit said customers who had reactions may ask for a full refund or replace their band with a different product.
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