A UK man allegedly developed Stevens Johnson Syndrome, a potentially fatal side effect to several medications, after taking ibuprofen to treat flu symptoms.

Jason Ryan, 28, started taking over-the-counter ibuprofen to treat oncoming flu when his skin started breaking out in a rash that turned out to be Stevens Johnson Syndrome (SJS). It was not the first time he had taken the medication and initially didn’t know that it could have been causing the blistering on his skin.

“He already had this rash, like shingles, and he was taking ibuprofen every four hours,” says Claire Ryan, Mr. Ryan’s wife. “It was all over his legs and back, I knew it wasn’t a sweat rash. He was taking the ibuprofen and the next day his feet came up in blisters like tennis balls.”

After the SJS symptoms worsened, Mrs. Ryan took her husband to the hospital where he was diagnosed with the skin reaction.

SJS usually starts out with flu-like symptoms such as fever, sore throat, and headache. The skin rash may initially start out as hives, but blisters will begin to develop on the skin and mucous membranes, especially the mouth, nose, and eyes. It usually culminates in the shedding of the skin–which means that the top layer of the skin has died. Eating, sleeping, urinating and even breathing can all become difficult. If blisters develop on the eye, it can cause blindness.

“There is no cure for it so it just has to run its course,” Mrs. Ryan told a local newspaper. “Jason’s body looked like a horror show, whenever he moved more skin would fall off. He was screaming, it was so raw.”

Mr. Ryan ended up going into a coma during the majority of the time that the illness was in full force.

“We were told it would last for 14 days, and he was in a coma for nine days,” she said.

Mrs. Ryan said that there were times in which she honestly wondered if her husband would make it.

Stevens Johnson Syndrome is fatal in about 5 percent of patients who contract it. Lesions can develop on internal organs such as the heart, lungs, kidneys, or liver, causing inflammation on those organs. It can also cause sepsis, a condition in which the bacteria from the infection enters the bloodstream. SJS can take months to recover from and can leave lasting damage.

Mr. Ryan said that he lost 40 pounds from the reaction and has still not fully recovered. He said that he is still extremely tired and weak.

“I get up, and I have to go and lie down at 12pm,” he said.

Another reaction that is closely related to SJS is Toxic Epidermal Necrolysis, in which 30 to 100 percent of the epidermis can separate from the body. In SJS, less than 30 percent of the skin is affected.

SJS and TEN are also potential side effects of other medications such as the anti-seizure medications Dilantin and Onfi, the popular antibiotic Zithromax, and the antidepressant Lamictal. It has also been linked to dozens of over-the-counter medications such as Advil, Tylenol, ibuprofen and more.