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McDonald's is pulling its "Step It" fitness trackers from Happy Meals just days after introducing it, following reports the wearable may give some children a rash.

"We have taken this swift and voluntary step after receiving limited reports of potential skin irritations that may be associated from wearing the band," Terri Hickey, senior manager of global corporate communications at McDonald's told NBC News in an emailed statement.

The children's wearable came in six bright colors. Some of the bands counted steps, while others blinked to indicate how fast the person wearing it was moving.

McDonalsd Fitness Tracker McDonalds

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In one instance, a Facebook post showing photos of a young boy wearing the fitness tracker and the mark his mother said it left on his arm has been shared more than 126,000 times since last weekend.

McDonald's was offering the trackers in its U.S. and Canada restaurants. Hickey said McDonald's was "fully investigating this issue" and would offer an alternative Happy Meal toy.

While fitness and McDonald's may not seem like a match, the tracker is one of the restaurant chain's latest health-centered initiatives. In 2012, the company began adding apple slices to Happy Meals.

McDonald's has also offered an assortment of healthier side dish options for parents who would rather their child forego french fries.

Read More: Hungry Special Forces Foil Hamburglars at French McDonald's

It seems even Olympic athletes — some of the fittest people in the world — can't resist the allure of the golden arches.

The McDonald's counter in Rio's Olympic Village is billed as one of the hottest tickets in town, with Olympians eager to unwind after an event.

It also doesn't hurt that the food is free. McDonald's has reportedly had to cap the order limit for hungry athletes at 20 items after many ordered a smorgasbord of fast food.

Australian badminton player Sawan Serasinghe showed off his impressive spread on Instagram, writing: "Now it's time to eat some junk food after months of eating clean!"