MS Relapse vs. Pseudorelapse: How to Tell Them Apart and Why Steroids Aren't Always the Answer

When your MS symptoms suddenly get worse, it’s natural to panic. Did another relapse hit? Is your disease progressing? But here’s the thing: not every spike in symptoms means your MS is actively attacking your nervous system. Many times, it’s something called a pseudorelapse - a temporary flare-up with no new damage, no inflammation, and no need for steroids. Mistaking one for the other isn’t just confusing - it can be dangerous.

What’s Really Happening When Symptoms Get Worse?

A true MS relapse is when your immune system launches a new attack on the myelin sheath around your nerves. This causes fresh inflammation, new lesions on your MRI, and symptoms that last at least 24 to 48 hours without any obvious outside cause. These can include sudden vision loss, leg weakness, balance problems, or numbness that didn’t exist before. If you’ve had MS for years, you know how unsettling this feels - and you’ve probably been through it before.

But here’s what most people don’t realize: up to a quarter of symptom flares aren’t relapses at all. They’re pseudorelapses. These aren’t caused by new damage. They’re caused by your body being under stress. Your nerves, already damaged from past MS attacks, are struggling to send signals. When something heats you up, gives you an infection, or pushes you too hard, those damaged pathways just can’t keep up. The result? Symptoms that feel exactly like a relapse - but they’re temporary.

Heat, Infections, and Stress: The Real Triggers Behind Pseudorelapses

If you’ve ever stepped out of a hot shower and suddenly couldn’t see clearly, you’ve experienced Uhthoff’s phenomenon. That’s a classic pseudorelapse. About 60 to 80% of people with MS who’ve had optic neuritis get this. Your vision blurs, your muscles feel heavy, your coordination slips - all because your body temperature rose just a degree or two. No new lesions. No inflammation. Just your nerves temporarily failing under heat stress.

But heat isn’t the only trigger. Infections are the biggest culprit. Urinary tract infections (UTIs) trigger pseudorelapses in nearly two out of every three cases. A cold, the flu, even a mild sinus infection can do it. Fever raises your core temperature, and suddenly, symptoms you thought were under control come roaring back. Physical exhaustion, emotional stress, and even extreme fatigue can do the same thing.

One patient on MyMSTeam shared: “I thought I was having a relapse when my legs gave out. Turned out I had a UTI. Took antibiotics, cooled down, and within hours, I was walking again. No steroids needed.” That’s the difference.

Why Steroids Don’t Work for Pseudorelapses - and Why They’re Risky

High-dose steroids like IV methylprednisolone are the go-to treatment for true MS relapses. They reduce inflammation, shorten the flare, and help you recover faster. About 70 to 80% of true relapses improve with steroids. But here’s the catch: steroids do nothing for pseudorelapses. Why? Because there’s no inflammation to calm down.

Giving steroids for a pseudorelapse is like using a fire extinguisher on a steamy mirror. It doesn’t fix the problem - it just adds new ones. Studies show that around 30 to 40% of patients get unnecessary steroids for pseudorelapses. And the side effects? They’re real. One in four people develop high blood sugar. Four in ten get severe insomnia. Three in ten report mood swings, anxiety, or even panic attacks. Some end up in the hospital with steroid-induced psychosis - not because their MS got worse, but because they were treated for the wrong thing.

A nurse with MS on Reddit wrote: “I’ve seen five patients get IV steroids for UTIs. One developed hallucinations. They didn’t need steroids. They needed antibiotics and rest.”

How to Tell the Difference - A Simple 3-Step Check

You don’t need an MRI or a neurologist to start ruling out a pseudorelapse. Here’s what to do the moment symptoms worsen:

1. Check your temperature. If you have a fever above 100.4°F (38°C), it’s likely a pseudorelapse. Infections are the #1 trigger.
2. Look for recent triggers. Did you take a hot bath? Get caught in the sun? Run errands all day? Skip a meal? Feel overwhelmed? These are red flags.
3. Wait 24 hours. True relapses don’t vanish quickly. If your symptoms start fading after you cool down, rest, or treat a UTI - it’s not a relapse.

If symptoms last longer than 48 hours and you’ve ruled out triggers, then it’s time to see your neurologist. They’ll likely order an MRI. New or enhancing lesions? That’s a true relapse. No new lesions? It’s probably a pseudorelapse.

What to Do When It’s a Pseudorelapse

The good news? Pseudorelapses don’t cause permanent damage. You won’t accumulate disability from them. The key is managing the trigger.

- For heat: Use cooling vests, stay in air-conditioned spaces, drink cold fluids, avoid hot tubs and saunas. A study showed patients using cooling gear recovered in under two hours.

- For infections: Treat UTIs early. Drink water, pee frequently, don’t ignore burning or urgency. A simple urine test can catch it before symptoms flare.

- For stress and fatigue: Rest. Say no. Schedule downtime. Burnout doesn’t just make you tired - it makes your MS symptoms worse.

Many patients keep a symptom diary. Write down what happened the day before the flare: Did you get sick? Were you hot? Did you sleep poorly? This helps you spot patterns. One woman in Exeter told me she noticed every time she skipped her morning coffee, her hands trembled more. Turns out, caffeine withdrawal was triggering her pseudorelapses.

Who’s Most at Risk - and Why It Matters

Pseudorelapses become more common the longer you’ve had MS. That’s not because your disease is worse - it’s because you’ve accumulated more nerve damage. Those damaged pathways are more sensitive to stress. People over 55 with significant disability are especially vulnerable. One study found 15% of older patients didn’t fully bounce back after a pseudorelapse - not because of MS progression, but because they got too weak from the episode and didn’t recover their mobility.

Also, people with progressive MS are more likely to experience pseudorelapses than true relapses. That’s because active inflammation slows down over time, but the damage stays. So even if your relapses are fewer, your symptoms can still spike - and you need to know why.

What’s New in Diagnosis - and Why It’s Better

A new tool called the MS-Relapse Assessment Tool (MS-RAT) is changing the game. It asks you questions about symptom duration, temperature changes, and how much your daily life is affected. It gives you a score - 92% accurate at telling true relapses from pseudorelapses. Some telehealth platforms now use it to help patients decide whether to go to the ER or just rest at home.

Research is also looking at blood tests. Neurofilament light chain levels - a marker of nerve damage - rise during true relapses but stay normal in pseudorelapses. That could mean one simple blood test will soon replace the need for an MRI in many cases.

Don’t Let Fear Drive Your Treatment

Too many people rush to steroids because they’re scared. But steroids aren’t a cure. They’re a tool - and only the right tool for the right problem. Treating a pseudorelapse like a relapse doesn’t help. It hurts.

If you’ve had a pseudorelapse before, you know the relief when you realize: this isn’t my MS getting worse. It’s my body asking for rest. Cooling down. Drinking water. Treating that infection. Sometimes, the best medicine isn’t a needle - it’s a cold towel, a quiet room, and a good night’s sleep.

When to Call Your Neurologist

Call your neurologist if:

• Symptoms last more than 48 hours
• You can’t identify a clear trigger
• Your symptoms are new, severe, or affect your ability to walk, see, or control your bladder
• You’ve had two or more flares in the last three months

Don’t wait. But don’t assume it’s a relapse. Bring your symptom diary. Mention any recent illness, heat exposure, or stress. Ask: “Could this be a pseudorelapse?”