Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis: What You Need to Know

Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) aren’t just rare skin conditions - they’re life-threatening emergencies that start with what feels like the flu and end with skin peeling off like a burn. These reactions don’t happen overnight. They creep up after you’ve taken a medication, sometimes for weeks, before everything falls apart. And when they do, they don’t just affect your skin - they attack your eyes, mouth, throat, and genitals. Survivors often carry the scars - physical and emotional - for the rest of their lives.

How SJS and TEN Are Connected

For decades, doctors thought SJS and TEN were two different diseases. Now we know they’re part of the same deadly spectrum. The only real difference? How much of your skin is destroyed.

If less than 10% of your body surface area loses its outer skin layer, it’s called Stevens-Johnson Syndrome. If it’s over 30%, it’s Toxic Epidermal Necrolysis. Between 10% and 30%? That’s the scary overlap zone. TEN is the worst. About 1 in 4 people with TEN don’t survive. Even if you make it out of the hospital, your body may never be the same.

Their names come from two doctors who first described them in the 1920s - Albert Stevens and Frank Johnson - but the most severe form got its name from Alan Lyell, who in 1956 noticed patients losing huge patches of skin after taking antibiotics. Today, we call it Lyell’s syndrome. But whether it’s SJS or TEN, the trigger is almost always the same: a drug.

What Happens When It Starts

You don’t wake up with peeling skin. It begins quietly - a fever that won’t break, a sore throat, a cough, burning eyes. You think it’s the flu. You take more ibuprofen. You rest. But within a few days, your skin starts to hurt. Not a rash. Not just red spots. It feels like it’s on fire. Then, flat red or purple patches appear on your chest and back. They spread fast. Within 24 to 72 hours, they turn into blisters. And then, the skin starts to come off.

That’s when the real danger begins. The top layer of your skin detaches from the layer below. It’s not a burn - it’s worse. Your skin doesn’t just blister - it sloughs off in sheets. A simple touch, even a blanket, can peel it away. This is called the Nikolsky sign. Doctors test for it gently - if the skin slides off with light pressure, you’re in trouble.

And it’s not just your skin. Your mouth cracks open. Your lips bleed. Your eyes swell shut. You can’t swallow. You can’t blink. Your genitals burn. In 9 out of 10 cases, your mouth is affected. In 8 out of 10, your eyes are. Half of all patients have three or more mucous membranes involved. This isn’t a rash. It’s a full-body betrayal.

What Drugs Cause It

Almost all cases are caused by medications. In over 80% of cases, doctors can trace it back to a single drug. Some are more dangerous than others.

• Antiepileptics - carbamazepine, phenytoin, lamotrigine - cause about 1 in 3 cases.
• Sulfonamide antibiotics - like trimethoprim-sulfamethoxazole (Bactrim) - account for 1 in 5.
• Allopurinol - used for gout - triggers 1 in 7 cases.
• NSAIDs - especially diclofenac and naproxen - are rising in risk.
• Nevirapine - an HIV drug - has been linked in many cases.

But here’s the chilling part: it’s not random. Your genes play a huge role. If you carry the HLA-B*15:02 gene - common in people of Southeast Asian descent - taking carbamazepine can increase your risk by 1,000 times. HLA-B*58:01? That one makes allopurinol 80 to 580 times more dangerous. That’s why places like Taiwan now require a simple blood test before prescribing these drugs. In just a few years, that test cut SJS/TEN cases by 80%.

Even infections can trigger it. Mycoplasma pneumoniae - the bug behind “walking pneumonia” - is the most common non-drug cause, especially in kids.

How Doctors Diagnose It

There’s no single blood test. No quick scan. Diagnosis comes from three things: your symptoms, your medication history, and a skin biopsy.

A biopsy looks under the microscope. In SJS/TEN, the top layer of skin dies completely - the whole thickness. And there’s almost no inflammation underneath. That’s what sets it apart from other conditions like staphylococcal scalded skin syndrome, which mostly affects babies and has a different pattern.

Doctors also use SCORTEN - a scoring system that predicts your chance of dying. It looks at seven factors: your age, whether you have cancer, your heart rate, how much skin is gone, your blood sugar, your kidney function, and your bicarbonate level. Each factor bumps up your risk. Three factors? You have a 35% chance of dying. Five or more? It jumps to 90%.

That’s why timing matters. The sooner you’re recognized, the better your odds.

What Happens in the Hospital

If you’re diagnosed, you’re not going to a regular ward. You’re going to a burn unit or intensive care. Your skin is as damaged as someone with a third-degree burn over half their body. Fluids leak out. Infection creeps in. You need fluids faster than an IV drip can give them - sometimes three to four times your normal daily amount.

First step? Stop every single medication you’re taking - even the ones you think are safe. Then, find the culprit. Was it the new painkiller? The seizure drug you started six weeks ago? That’s critical. You can never take it again.

Wound care is brutal. No sticky bandages. No ointments that stick. Just soft, non-adherent dressings. Your skin needs to heal from the inside out. Pain control is essential - you’re in agony. Many need morphine just to sleep.

Eye care? Daily. Your corneas can scar. Your eyelids can stick together. Without specialists, you could lose your vision. About half of survivors have lifelong dry eyes. A quarter have permanent scarring. A few go blind.

Treatment Controversies

There’s no magic bullet. And no one agrees on the best treatment.

IVIG - a concentrated antibody treatment - was once thought to help. But big studies later showed it doesn’t lower death rates. Steroids? They reduce inflammation, but they also make infections worse. Some doctors use high-dose pulses early on. Others avoid them completely.

Cyclosporine - a drug used for organ transplant patients - has shown real promise. One 2016 study found it cut death rates from 33% to just 12.5%. It works by calming the immune system’s attack on the skin.

The most exciting new option? Etanercept. It blocks a key inflammatory chemical called TNF-alpha. In a 2019 study, 12 patients treated with etanercept within 48 hours of symptoms had zero deaths. In past cases without it, over 30% died. It’s not yet standard everywhere, but it’s changing how doctors think about treatment.

Long-Term Damage

Surviving doesn’t mean healing. Six out of ten people have lasting problems.

• 50-80% have chronic dry eyes, light sensitivity, or blurred vision.
• 70% have patches of darker or lighter skin that never fade.
• 40% have scars that pull or tighten.
• 25% lose nails or grow them deformed.
• 15% develop urethral strictures - making urination painful or impossible.
• 10% get vaginal scarring that causes pain during sex.

And then there’s the invisible damage. Four in ten survivors develop PTSD. The experience - the pain, the isolation, the fear of skin falling off - stays with you. Many can’t sleep. They flinch at touch. They avoid hospitals. They never take another pill without fear.

Can It Be Prevented?

Yes - but only if you know your risk.

If you’re of Asian descent and your doctor wants to prescribe carbamazepine for seizures or bipolar disorder, ask: “Have you tested me for HLA-B*15:02?” If you have gout and allopurinol is being recommended, ask: “What’s my HLA-B*58:01 status?”

Since 2022, the FDA approved a point-of-care test for HLA-B*58:01. Results in four hours. No waiting weeks. That’s huge. It means you can get your gout treatment without risking your life.

Even if you’re not in a high-risk group, always tell your doctor about every medication you’ve taken in the last six weeks - even over-the-counter ones. A simple painkiller, taken just once, could be the trigger.

And if you ever get a fever, rash, and mouth sores after starting a new drug - don’t wait. Go to the ER. Say: “I think this might be Stevens-Johnson Syndrome.” Time is everything.

What’s Next

Researchers are now hunting for more genetic markers. The iSCAR global registry tracks over 1,200 cases to find patterns we’ve missed. Early trials are testing drugs that block granulysin - the molecule that literally kills skin cells in SJS/TEN. If it works, it could be the first targeted treatment.

But until then, the best defense is awareness. Know your meds. Know your genes. Know the signs. Because this isn’t a rare disease that happens to someone else. It can happen to anyone - and it happens faster than you think.