MS Flares, Relapses, Exacerbations: How Much Do You Know?

New to MS? Columnist Ed Tobias explains what an MS flare-up is

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by Ed Tobias |

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“I was told I’m in a flare-up,” a newly diagnosed person with multiple sclerosis (MS) wrote to a Facebook group the other day. She said the flare-up had been going on “for a while now” and wondered when she could expect it to calm down.

After I pondered the thought of an MS newbie needing more information about flare-ups, I realized that others are probably in the same boat. So here are some MS flare-up facts:

What’s in a name?

You can call it a flare-up, relapse, or exacerbation — they’re all the same. An exacerbation is what it was called when I was diagnosed with MS in 1980. I guess it sounds more scientific than the other terms. I think relapse is a better description, though, because it’s what actually happens to someone with relapsing-remitting MS: Symptoms act up for a while and then ease, or remit. Flare seems to be the current favorite term, meaning that symptoms flare up for a while.

By the way, The Consortium of Multiple Sclerosis Centers prefers the simple term “relapsing MS” rather than relapsing-remitting MS. This underscores that MS disease activity continues even though the relapse has eased and progression may not be evident.

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Is this really a relapse?

There are also flares and pseudo-flares. In another social media group, someone wrote that she was having a pseudo-flare that lasted about 40 days. That’s not pseudo, that’s the real thing.

A pseudo-flare is triggered by one or more external factors — a hot day, a fever, or stress, for example. A couple years ago, the stress of having to take a driving test on a hot day at age 72 caused me a pseudo-flare. That afternoon, my fatigue kicked up and booted me into bed by 8 p.m. The next morning, it was difficult to get out of a chair, much less stand or walk. But I was back to my normal MS self by the end of the day.

In a real flare, new symptoms appear or old ones worsen. They last for at least 24 hours and can’t be explained away by things like a change in body temperature, an infection, or stress. Sometimes it’s over in a few days. Sometimes a flare can last a couple of months. A flare lasting over a month isn’t pseudo — it’s the real McCoy.

What can you do about it? 

Flares can be reduced by using one of the many available disease-modifying therapies (DMTs). When they do occur, their symptoms can be limited, and sometimes reversed, by steroid treatments. These medications include Solu-Medrol (methylprednisolone), dexamethasone, and prednisone.

For several years after I was diagnosed (way before any DMTs were approved), my flares were treated with several days of Solu-Medrol infusions, followed by a tapering down with prednisone pills for about a week. The purified hormone Acthar Gel is sometimes used when steroid treatments are ineffective.

My steroid treatments certainly helped, but steroids can cause bone loss, and I’m concerned that the sporadic hip pain I now have could be related to their use. So, as with any treatment, the benefits and risks need to be weighed. And as always, consult your healthcare team before taking any medications or making any adjustments to your treatment regimen.

Since flare-ups are common in MS, understanding whether what’s happening is a pseudo-flare or the real thing should help you decide whether or not it’s time to call your neurologist and seek treatment.

You’re invited to visit my personal blog at

Note: Multiple Sclerosis News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website. The opinions expressed in this column are not those of Multiple Sclerosis News Today or its parent company, BioNews, and are intended to spark discussion about issues pertaining to multiple sclerosis.


Leanne Broughton avatar

Leanne Broughton

Relapsing & Remitting MS was a misnomer for me. With my relapses, big or small, the results only remiited a little. My MS continued in a slow progression. I had friends say I had the "good" kind of MS, thinking remittance meant I go back to normal. Never.

Ed Tobias avatar

Ed Tobias

Hi Leanne,

It sounds as if you have what they call "active" secondary progressive MS...slow progression while flares also continue. I'm sorry that's the case and I hope that you can find a treatment that will move you from "active" to "non-active."


VC avatar


A nice well-explained article ideal for sharing in those online spaces that perpetuate misinformation. The number of people who rely on social media platforms to get explanations on this sort of stuff never fails to astonish me. There are endless rubbishy posts put up by ill-informed people who themselves learnt everything they know from social media and learnt it wrong, which when re-posted then misinforms whole new "generations" of newly diagnosed people, who then go on to themselves repeat the "crime" online. I've lost count of the number of times I've seen social media posts oh-so-earnestly explaining the difference between a "flare" and a "relapse" and an "exacerbation" with all sorts of invented delineation rules. This article's definitely gone into the bookmarks for use with helping to help dispel some of the garbage posted elsewhere - as people tend to not believe unless there is a link to something else.

Ed Tobias avatar

Ed Tobias

Hi VC -

What a nice comment. All of us on the MS News Today website, and at our parent company BioNews, are committed to providing factual information, and much of it comes from patient-columnists like me. I try to counter what I call the dangerous Dr. Internet and to encourage reading beyond the headlines. (So many people don't.) I even wrote a column, several years ago, about that.

Thanks for taking the time to let me know you appreciate the effort.



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