MS Relapse: How to Recognize it, When to Call Your Neurologist, and What to Expect

If you're living with multiple sclerosis, few things are more unsettling than a new or unfamiliar symptom showing up, or an old one returning stronger than expected. The questions come fast: Is this a relapse? Should I call someone? Is something getting worse?

Those questions are completely valid. One of the most common concerns my patients share is not knowing whether what they're feeling is a true relapse or something temporary. This article is meant to help you understand the difference, so you can feel more confident about when to reach out to your neurologist and what to expect if treatment is needed.

What Is an MS Relapse?

An MS relapse (also called an exacerbation, flare-up, or attack) is a period of new or worsening neurological symptoms caused by fresh inflammation in the brain or spinal cord. Neurologists generally look for a few key features when evaluating whether a symptom change qualifies as a true relapse:

• New or worsening symptoms that weren't present at your last stable baseline
• Duration of at least 24 hours, typically lasting days to weeks
• At least 30 days since your last confirmed relapse
• No fever or infection that could explain the symptom change

Relapses occur because the immune system launches a new attack on myelin — the protective coating around nerve fibers — a process called demyelination. This creates a new area of neuroinflammation that disrupts nerve signaling.

How to Recognize a True Relapse

New or Returning Symptoms

True relapses typically involve symptoms that develop over hours to days. Common relapse symptoms include:

• New or worsening numbness or tingling in a limb, the trunk, or the face
• Weakness in an arm or leg that wasn't there before
• Vision changes such as blurring, double vision, or painful vision loss in one eye
• Dizziness or new balance problems
• Significant worsening of brain fog or cognitive function
• New bladder urgency or difficulty emptying the bladder
• Increased spasticity or muscle stiffness

The key distinction is whether a symptom is truly new. Stable numbness in your left foot that gets slightly worse on a hot day is different from new numbness appearing in your right hand for the first time. When something feels genuinely new or different from your baseline, that's worth a call to your neurologist.

Pseudo-Relapses vs True Relapses

Pseudo-relapses are temporary worsenings of existing symptoms that don't involve new inflammation. They're actually far more common than true relapses — and they can feel identical in the moment.

The most common pseudo-relapse trigger is the Uhthoff phenomenon — heat sensitivity that temporarily worsens MS symptoms. A hot shower, exercise, fever, or even a warm day can unmask symptoms that improve once you cool down. This can be frightening when it happens, especially the first time. Many of my patients describe a moment of real panic when they notice weakness after exercise, only to find everything returns to normal within 30 minutes of cooling down. Once you recognize the pattern, it becomes much less alarming — but it's always OK to call your neurologist if you're not sure what you're experiencing.

Common Relapse Symptoms

While any MS symptom can appear during a relapse, some are more common:

• Optic neuritis — painful vision loss in one eye, often the first or most recognizable MS relapse type
• Sensory relapses — numbness, tingling, or unusual sensations in new areas
• Motor relapses — weakness in a limb, difficulty walking, foot drop
• Brainstem relapses — double vision, vertigo, slurred speech, swallowing difficulties
• Spinal cord relapses — band-like tightness around the torso (MS hug), leg weakness, bladder/bowel changes

What to Do When You Think You're Having a Relapse

Call Your Neurologist

Your MS neurologist is the best person to help you figure out what's going on. Most relapses don't require an emergency room visit — they're best evaluated by someone who knows your history, your baseline, and your treatment plan. Your neurologist can:

• Help determine whether this is a true relapse or a pseudo-relapse
• Order an MRI to look for new inflammatory activity
• Prescribe steroid treatment if appropriate
• Evaluate whether your long-term treatment plan needs adjustment

If your neurologist offers telehealth appointments, this can be an especially efficient way to get evaluated quickly without having to travel while you're symptomatic.

What Your Neurologist Will Want to Know

Before your call or visit, it helps to think through a few details — not because you need to diagnose yourself, but because this information helps your neurologist make the right call faster:

• What symptoms are new or different from your usual baseline
• When they started and how they've progressed
• Whether anything makes them better or worse
• Whether you've had any recent illnesses, even something mild like a cold
• Whether you've had a fever

Ruling Out Infection

One of the first things your neurologist will consider is whether an infection could be driving the symptom change. Infections — particularly urinary tract infections, which are more common in people with MS — can cause dramatic worsening of existing symptoms that looks and feels like a relapse but resolves once the infection is treated. This is one of many reasons why having your neurologist involved early matters: they can order the right tests and sort things out efficiently.

How Relapses Are Treated

High-Dose Corticosteroids

The standard treatment for an MS relapse is high-dose corticosteroids, most commonly oral prednisone or intravenous methylprednisolone given over three to five days. Steroids work by reducing inflammation at the site of the new attack and shortening the duration of the relapse.

An important nuance: steroids speed up recovery, but the eventual degree of recovery tends to be similar whether steroids are used or not. The benefit is getting you back to function faster — which matters a great deal when a relapse is affecting your ability to work, care for your family, or manage daily life.

Side effects during the high dose steroid days — insomnia, a metallic taste, mood changes, water retention and increased appetite — are common but temporary. They typically resolve within a week or two after the course is finished.

Plasma Exchange (Plasmapheresis)

For severe relapses that don't respond to steroids, plasma exchange may be considered. This procedure removes antibodies from the blood that may be contributing to the attack. It's typically reserved for:

• Severe relapses with significant disability
• Relapses that don't improve after a full course of IV steroids
• Attacks affecting critical functions like vision or walking

Supportive Care

Recovery from a relapse goes beyond medication:

• Rest — Your body needs energy to heal. This is a time to listen to what it's telling you.
• Physical therapy — Can help maintain strength and mobility during recovery
• Occupational therapy — Helps with strategies for daily tasks affected by symptoms
• Cooling strategies — If heat worsens your symptoms, staying cool with fans, cooling vests, or air conditioning can make a real difference

Recovery Timeline

Recovery from an MS relapse is gradual, and it helps to know what the process generally looks like so it feels less uncertain:

• First 1–2 weeks: Symptoms typically peak and may begin to plateau
• Weeks 2–4: Early improvement often begins, especially with steroid treatment
• Months 1–3: Most recovery occurs during this period
• Months 3–12: Continued gradual improvement is possible, though slower

Not every relapse results in complete recovery. Some relapses, particularly those affecting motor function, may leave residual symptoms. This is one of the reasons why preventing relapses through disease-modifying therapy is such a priority in MS care.

Something I find helpful to share with my patients: recovery from a relapse is rarely linear. You might feel noticeably better for a few days, then plateau, then improve again. That unevenness is normal. What matters is the overall trajectory over weeks and months, not how any single day feels.

How to Reduce Your Risk of Future Relapses

The single most important factor in preventing relapses is staying on an effective disease-modifying therapy. Monitoring tools like the neurofilament light chain blood test can help detect subclinical disease activity early. If you're having relapses despite treatment, it may be time to discuss whether a more effective therapy is available. For a detailed comparison of treatment options, see our MS treatment guide or our comparison of B-cell therapies. If you're planning a pregnancy, timing medication changes around relapses requires careful coordination — see our guide on MS and pregnancy.

Beyond medication, research supports several lifestyle strategies:

• Prevent infections: Practice good hygiene, get recommended vaccinations, and address infections promptly
• Manage stress: Chronic stress may increase relapse risk — mindfulness, therapy, and stress-reduction techniques are all worth exploring
• Optimize vitamin D: Low vitamin D levels are associated with higher relapse rates — your neurologist can check your levels and advise on supplementation
• Exercise regularly: Regular physical activity reduces fatigue and may have a protective effect
• Prioritize sleep: Poor sleep increases inflammation and worsens MS symptoms
• Avoid smoking: Smoking accelerates MS progression and increases relapse frequency

For a comprehensive guide to lifestyle strategies, see our article on lifestyle changes to protect your brain health in MS.

When to Reach Out to Your MS Specialist

Beyond active relapses, it's worth connecting with your neurologist if:

• You're having more frequent relapses than before
• Your recovery from relapses feels less complete over time
• You're noticing gradual worsening between relapses
• Your symptoms are unusually severe, raising questions about whether you may have NMO or MOGAD rather than MS
• You want to discuss whether your current treatment is the right fit

Living with MS means having a partner in your neurologist — someone who knows your history and can help you navigate moments of uncertainty without guesswork. At Achilles Neurology Clinic in Beverly Hills, that's the kind of relationship we build with every patient. If you're experiencing new symptoms or simply want to make sure your treatment plan is keeping up with your disease, we're here for that conversation.

Frequently Asked Questions

How do I know if I'm having an MS relapse?

A true MS relapse involves new or worsening neurological symptoms that last at least 24 hours and occur at least 30 days after your last relapse. Symptoms develop over hours to days and may include vision changes, new numbness or weakness, balance problems, or significant fatigue. Temporary symptom worsening from heat, stress, or illness is usually a pseudo-relapse, not a true relapse. Your neurologist can help you tell the difference.

How long does an MS relapse last?

Most MS relapses last days to weeks, with symptoms typically peaking within the first week. Recovery usually begins within two to three months, though some improvement may continue for up to 12 months. The degree of recovery varies—some people return to baseline while others may have residual symptoms.

What is the treatment for an MS relapse?

The standard treatment is high-dose corticosteroids, typically oral prednisone or intravenous methylprednisolone given over three to five days. Steroids reduce inflammation and can speed recovery, though they don't change the final degree of recovery. For severe relapses that don't respond to steroids, plasma exchange (plasmapheresis) may be considered. Your neurologist will recommend the best approach based on the severity of your symptoms.

Can stress trigger an MS relapse?

Research suggests that significant and prolonged stress may increase the risk of MS relapses, though the relationship is complex. Infections are the most clearly established relapse trigger, responsible for about one-third of relapses. Other potential triggers include sleep deprivation and extreme heat exposure.

Does every MS relapse cause permanent damage?

Not every relapse causes permanent damage. Many people recover fully or nearly fully from relapses, especially early in the disease and with prompt treatment. However, some relapses may leave residual symptoms. This is why staying on disease-modifying therapy to prevent relapses is so important.

About the Author

Dr. Achillefs Ntranos MD

Board-Certified Neurologist
Achilles Neurology Clinic

Dr. Achillefs Ntranos MD is a board-certified neurologist and MS specialist known for his thorough evaluations and compassionate approach. Originally from Greece, he trained at Johns Hopkins University and Mount Sinai Hospital before founding Achilles Neurology Clinic in Beverly Hills to deliver comprehensive, patient-centered neurological care. He specializes in MS, autoimmune neurology, neuropathy, headaches, and other neurological disorders, blending research-driven insights with personalized treatment plans.

Learn More About Dr. Ntranos(310) 774-7025