Acetaminophen, the active ingredient used in Tylenol, has been linked to Stevens Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN), both severe and potentially deadly skin conditions.

Tylenol is not the only medication that has been found to cause Stevens Johnson Syndrome in patients. Lamictal and Zithromax have also been linked to the reaction. On Aug. 1, 2013, the U.S. Food & Drug Administration (FDA) warned the public that both prescription Tylenol and its over-the-counter variety carry the same risk of SJS.

According to reports, the FDA discovered the risk of skin diseases while reviewing adverse events reported in its database between 1969 and 2012. It was during this period that 107 cases of significant skin reactions were reported; 67 people were hospitalized and 12 people died.

SJS normally occurs within the first two weeks of taking the medication. If left untreated, it can be fatal. The victim will first develop flu-like symptoms. It will be followed by rash, blister, and eventual detachment of the skin. In SJS, the rashes and blisters can cover up to about 30 percent of the body, while Toxic Epidermal Necrolysis (TEN) can leave about 90 percent of the body covered in blisters and rashes. This condition can also cause blindness and the need for amputation if not treated properly.

About 300 new cases of Stevens Johnson Syndrome are reported in the United States every year. According to medical experts, most of these cases could have been avoided if patients were aware of this possibility and if unusual symptoms when taking medication are immediately reported to doctors.

“This new information is not intended to worry consumers or health care professionals, nor is it meant to encourage them to choose other medications. However, it is extremely important that people recognize and react quickly to the initial symptoms of these rare but serious side effects, which are potentially fatal,” FDA Deputy Director Dr. Sharon Hertz said in issuing the warning.

The FDA also required manufacturers to add warning labels to all prescription medications that contain acetaminophen.