Some owners of the Fitbit Force, the company's latest wrist-worn activity tracker that measures steps, stairs climbed, calories burned and sleep, are reporting severe skin irritation, including rashes, blisters and peeling skin.
Some of these people, who have taken to Fitbit and Engadget online forums as well as to Twitter with complaints, have reported seeking medical care for injuries they say were caused by the band. Fitbit Force came out last fall and retails for $130.
News of Force-related skin issues was first reported Monday by Consumerist.
Wearable devices, or so called wearables, with sensors that connect to a network or an app and collect data that can include sleep and heart rate, were hot items at last week's International CES, the annual technology trade show, in Las Vegas. The Fitbit complaints come as the company is emerging as a market leader in the nascent category. According to NPD Group, a market research firm, Fitbit was responsible for 68 percent of the full-body trackers sold in the year ending Jan. 4. All Fitbit Force bracelets are currently shown as backordered on Fitbit's website.
In a statement to The Huffington Post, Fitbit said "numerous factors" may "cause skin irritation," including sensitivity to the device's stainless steel, which contains nickel, "reactions to bacteria that can accumulate in wristbands, or a sensitivity to the material of the band elastomer." The company said it would offer refunds or exchanges to those affected.
Based on interviews with five people as well as posts on the Fitbit forum, which on Monday evening had ballooned to 24 pages, rashes on the wrists of some Force owners seem to follow a similar pattern: A person wears Force for a few weeks without incident, and, after recharging it a few times, notices redness under the main part of the device, which houses the sensors, battery, display and charging port.
Mike Townsend, 56, a retired air traffic controller from River Falls, Wis., said his skin became irritated after wearing Force for about two or three weeks. He initially thought the irritation was caused by bacteria, so he used alcohol wipes to clean the bracelet and made sure to clean his wrist after exercising. But the rash got worse. 

"Apparently I have a high threshold for pain, because it got to the point where I wasn't able to wear anything on my left wrist," Townsend said in an interview with The Huffington Post. "Even a tight-fitting shirt would be an irritant."