Health specialists have put out a warning over a new craze taking social media by storm, where people set themselves on fire.

Called "The Fire Challenge", young people are daring each other to set themselves alight, a dangerous feat that staff at a specialist burns unit at Swansea's Morriston Hospital in Wales say is done to boost their popularity and 'likes' online, reports Metro.

But the dares are getting attention for all the wrong reasons, with many young people being hospitalised with serious burns, which often require surgery and life-support treatment.

"I can understand there is pressure on young people to gain acceptance or boost their online profiles by doing such risky things as these challenges," said Jeremy Yarrow, a Morriston Hospital plastic surgeon.

"But from the patients I see, the results can be very different, with some requiring life support treatment and many left with lifelong scars. In some severe and sometimes life-threatening cases, they are admitted to hospital for long periods of time for complex surgery resulting in long term mental and physical issues," he said.

One of those young people was 12-year-old Timiyah Landers from Detroit, who burned 49 percent of her body after flames engulfed her.

Ms Landers was later taken to hospital and put on a ventilator in intensive care.

Abertawe Bro Morgannwg University Health Board is warning wannabe social media stars to not take part in the online dares.

The craze is thought to have begun in 2012 in the United States after YouTuber 1BlazinEagle1 uploaded a video of him lighting his chest hair on fire.

The video was viewed more than 100,000 times by 2014.

Newshub.