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Fitness trackers
It's well known that costume jewelry can cause an allergic reaction, as these baubles are often made with materials like nickel. Your fitness tracker may also be made with irritating metals. "Skin allergies to new wearable technology is something that may become more common," says Sarena Sawlani, MD, Medical Director of Chicago Allergy & Asthma. In fact, nickel is one of the most common causes of allergic skin rashes, affecting more than 18 million people in North America, according to the American Academy of Dermatology. In 2014, Fitbit recalled one million of these wristbands because of reactions that resulted in redness, rashes or blisters. These rashes happen hours to days after wearing them, so the culprit may not be obvious. An allergist can do a patch test to see what's setting off your skin woes.