A photograph showing the wrist of Steven Adams, which he said he took after wearing his Fitbit Force for about a month.

A photograph showing the wrist of Steven Adams, which he said he took after wearing his Fitbit Force for about a month. Photo: Steven Adams

Fitbit is offering refunds and replacements for its latest wearable fitness device after users reported the gadget was causing skin irritations.

Reports of rashes caused by the Force surfaced in December on the company's forum, where several users said they may be having an allergic reaction to the device.

"I've had my Force for about a month now," one user said. "About four days ago I started getting the burn/rash. I quit wearing it so my arm could heal but it is about the size of a baseball now and it burns. It also has started to swell. I've tried putting creams on it but it hasn't helped."

Another user's skin irritation after using Fitbit Force.

Another user's skin irritation after using Fitbit Force.

Another user posted an image of the irritation on the web.

The Force is not yet on sale in Australia, although many users have ordered the device online from overseas.

It came out in the US in October for $US129.95 ($145). Users wear the gadget on their wrists to track how much exercise they do throughout the day. The gadget communicates with an app on their smartphone to relay statistics in real time.

Fitbit addressed the skin irritation situation this week, saying it was aware of the problem.

"Our customers are our top priority, so we already have been taking steps to make this right with any customers who feel that they have an allergy related to their Fitbit device including offering a refund or a choice of a replacement tracker," the company said in a statement to Consumerist. "Fitbit will handle all shipping costs and will provide a refund in any difference in price."

Users of other wearable fitness devices, such as Nike's FuelBand and Jawbone's Up24, have reported similar skin irritations.

Dermatologist Dr J. Todd Williams told Engadget the most likely cause of the rashes was a build-up of moisture and bacteria. Many users never take off the water-resistant devices, causing water and sweat to build up, which can cause sores and rashes in people with sensitive skin.

Fitbit has not announced plans to recall the Force.

Los Angeles Times, Fairfax Media