Stevens-Johnson syndrome: Causes, triggers, and what to do if you suspect it

When your skin starts to blister and peel after taking a new medicine, it’s not just a rash—it could be Stevens-Johnson syndrome, a life-threatening allergic reaction that attacks the skin and mucous membranes. Also known as toxic epidermal necrolysis in its most severe form, this condition doesn’t wait for permission—it hits fast, and it’s dangerous. Most cases start with flu-like symptoms: fever, sore throat, burning eyes. Then, within days, red or purplish patches appear on your skin, turning into blisters that spread and shed like burns. It’s not contagious. It’s not normal. It’s your body screaming that something in your system is killing your skin.

This reaction is almost always tied to drugs, specific medications that trigger an extreme immune response. Antibiotics like sulfonamides, anticonvulsants like carbamazepine, and painkillers like allopurinol are the usual suspects. Even common OTC drugs like ibuprofen or naproxen have caused it in rare cases. The problem? You might not know you’re at risk until it’s too late. Some people have a genetic marker—HLA-B*1502—that makes them far more likely to react badly to certain drugs, especially in Asian populations. Doctors don’t always test for it, so you need to know the signs.

Stevens-Johnson syndrome doesn’t just hurt your skin. It can wreck your eyes, mouth, throat, and genitals. Blisters in your mouth make eating or drinking impossible. Your eyes can scar permanently if not treated fast. That’s why hospitals treat this like a burn injury—with IV fluids, pain control, and sometimes ICU care. Stopping the drug right away is step one. No waiting. No hoping it gets better. If you’re on a new medicine and your skin starts peeling or you get mouth sores with a fever, go to the ER. Don’t text your doctor. Don’t wait till morning. This isn’t a Zoom appointment situation.

What you’ll find below isn’t a list of every drug that causes it. It’s real stories from people who’ve been there, and the medical research that explains why it happens. You’ll see how antibiotics can go wrong, how pain meds can trigger it, and what alternatives exist for people with high risk. These aren’t theoretical articles. They’re guides written by people who’ve seen the damage, studied the patterns, and want you to avoid it.