A Welsh teenager was recently diagnosed with a life-threatening skin reaction reportedly caused by the flu medication Tamiflu.

Tamiflu is a drug that can lessen the severity of the flu, a respiratory infection caused by various strains of the influenza virus. The drug itself can have a variety of serious side effects, and is generally used to combat particularly dangerous flu strains, or to curb the infection in high-risk patients. However, outbreaks of more and more serious flu strains, such as the infamous H1N1 “swine flu” have made Tamiflu — and possibly its side effects — more common.

Tamiflu works by blocking the receptors that the flu virus commandeers to invade host cells. It may also prime the immune system to fight the virus. The active ingredient, Oseltamivir, is actually a mostly-inactive compound. However, within the human body, chemical reactions in the liver modify the molecule, “activating” it. Once active, the compound makes it harder for the virus to spread and reproduce within the body. There are concerns that this compound can trigger serious side effects, including autoimmune reactions.

What Is SJS?

Stevens-Johnson Syndrome, or SJS, is an autoimmune disease. Autoimmune diseases or reactions are situations wherein the body attacks itself, using the immune system it usually uses to fight off infection. In SJS, the body attacks its own skin, causing a painful rash, which escalates to blisters, then sores, and finally ulcers. The damage can spread to the surface of the internal organs and the eyes. In some cases, it can even prove fatal. The reaction is almost always triggered by various medications, including Tamiflu.

The Welsh SJS Case Study

A case study published in the British Journal of General Practice described the recent case of a 17-year-old who suffered SJS from Tamiflu. The teenager had received Tamiflu two weeks prior and taken no other medication. The attending physicians diagnosed the teen as having SJS caused by Tamiflu. When he arrived at Singleton Hospital in Wales, he had a rash covering his limbs and trunk. The rash had progressed to ulcers on his skin. He also suffered from blurred vision. Among the problems, the Welsh teenager suffered from coronal ulcers, which could have blinded him.

With supportive treatment, the teen recovered. The report by the staff of  Singleton Hospital in Swansea concluded that “given the sometimes minimal benefits, it may be advisable to think twice before issuing a prescription; however, with increasing use, we are likely to see more cases of severe skin reactions in the future.”