Relapsing remitting MS (RRMS)

In relapsing remitting MS (RRMS) people have attacks of new and old symptoms, this is called a relapse. Around 85% of people with multiple sclerosis are diagnosed with RRMS. Taking a disease modifying therapy (DMT) could mean fewer relapses and slow down your MS.

The relapsing remitting label can help explain MS to others and help you to find the best treatments. But it can't predict exactly how MS will affect you.

For most people with MS, this is the way their MS begins, except for the small group of people (15%) diagnosed with primary progressive MS.

Relapsing remitting MS (RRMS) explained

Relapsing remitting MS is a type of MS where you have relapses (symptoms getting worse) followed by recovery (that’s when it’s “remitting”).

Your disability doesn’t get worse between relapses but after each relapse it can end up worse than before. As time goes on your body finds it harder to repair the damage each relapse brings. So your disability is likely to get worse, especially if you don’t start treatment.

How is relapsing remitting MS different from other types of MS?

Relapsing remitting MS is the most common type of MS. The other types are primary progressive MS and secondary progressive MS.

With progressive types of MS the condition gradually gets worse over time. Some people also have relapses, but there’s clear progression of symptoms that’s separate from the relapses.

MS relapses are caused when your immune system attacks the protective covering (called myelin) around nerves in your brain and spinal cord. These attacks damage the myelin. Inflammation around the nerves is the sign of an attack. The damage to the myelin means these nerves don’t work like they should, and this causes your MS symptoms.

What is a relapse?

A relapse is defined by "the appearance of new symptoms, or the return of old symptoms, for a period of 24 hours or more – in the absence of an infection or a change in your core body temperature. On top of that, 30 days must’ve passed since your last relapse or flare up of symptoms. Symptoms you have experienced before, or perhaps grown used to dealing with, might appear in a different part of the body.

Relapses can vary from mild to severe. At their worst, acute relapses may need hospital treatment, but many relapses are managed at home, with the support of your GP, MS specialist nurse, and other care professionals.

Symptoms which come and go can sometimes be considered a relapse – they don’t always have to be continuous. For example, some people experience a shock-like sensation when they bend their neck. This can be considered a relapse if, for 24 hours or more, this happens every time you bend your neck.

Medical staff might call relapses things like an attack, flare-up, exacerbation, acute episode or clinical event.

MS relapse symptoms

Relapse symptoms are different for everyone because MS affects each person differently. Relapse symptoms might include:

  • Trouble with balance
  • Fatigue
  • Sight difficulties
  • Feeling weak
  • Heat sensitivity
  • Lack of coordination
  • Numbness or tingling
  • Difficulty thinking clearly
  • Frequent, urgent need to pee

How long does an MS relapse last?

In relapses, symptoms usually come on over a short period of time – over hours or days. They often stay for a number of weeks, and for most people are usually over within a month. But this can vary, from very short periods of only a few days, to many months.

Will I recover completely from a relapse?

People often make a very good recovery from a relapse, with complete remission. However, this is not always the case and around half of all relapses may leave some lingering problems, however slight.

This is because, if the damage to myelin is severe, then some symptoms remain, though they may still improve over the following months.

Our understanding of how MS attacks the body is changing. MS specialists used to think that once a relapse was over, the damage to your brain and spinal cord stopped and no new damage was happening. But now we know that even when you aren't having relapses MS can still be causing damage.

This damage can be happening even if there are no signs of it that you might notice, such as a relapse. That's why treatment with a disease modifying therapy (DMT) should be offered to you as close to when you're diagnosed as possible.

MS doesn’t only cause damage to the myelin coating around the nerve. The nerve fibre inside can also get damaged. This is what can cause “progression”, where symptoms get gradually worse, even without a relapse

Many people with relapsing remitting MS eventually go on to have secondary progressive MS.

What can trigger or prevent MS relapses?

Many people with MS feel they can identify things that might trigger a relapse for them. Unfortunately, what appears to affect one person doesn’t always apply to someone else, and research has not yet found what triggers every relapse that people have. This makes it hard to give definite strategies for avoiding relapses altogether. But there is one thing we know that can reduce the number of relapses people get: treatment with a disease modifying therapy (DMT).

Disease modifying therapies

Disease modifying therapies (DMTs) are used to treat MS where you get relapses or where there’s inflammation on your MRI scans. They can reduce how many relapses you get and can slow down the rate at which disability happens to you. But they can't undo any permanent disability that you already have.

To reduce the risk of permanent damage to your body, you should be offered a DMT as soon as possible after a diagnosis of relapsing MS. DMTs work better the sooner you start them but taking one later can still have benefits.

These drugs can have side effects, some serious, but not being treated means the risk of more relapses and more long-term disability.

Find out more about DMTs


Over the years, many studies have looked at whether there is a link between psychological stress and MS getting worse. The evidence is not absolutely clear, but many experts believe that stress might be one of many factors which could increase the risk of a relapse. Anecdotally, many people affected by MS cite stress as a major factor in bringing on a relapse.


Some infections, for example a bladder infection, may also make a relapse more likely. For this reason, people with MS are encouraged to treat infections early and to avoid things that can cause them. That’s why people with MS are advised to have an annual flu jab, for example.


There’s no proven link between vaccinations (for example, for flu, hepatitis B or nearly all travel vaccines) and a relapse. If you're going to an area where a serious infectious disease is prevalent, it's generally far better to have a vaccination than to risk serious illness, which could have far worse consequences.


Many women with MS find that they have fewer relapses during pregnancy. But in the months after the baby is born the risk of a relapse often goes up. So, soon after the birth, it’s recommended that the mother starts a DMT (or goes back to taking the one she was on before the pregnancy).

Find out more about pregnancy and MS


Giving up smoking (or never starting) also means you’re likely to have fewer relapses in the long run. That’s because smoking makes you more prone to infections (of the chest or lungs, but also colds and flu), and these can trigger a relapse.

Smoking also stops some DMTs from working as they should. If you smoke while on some DMTs, you have a higher chance of a relapse compared to people on the same drug who don’t smoke.

Vitamin D

Some studies show being low in vitamin D is linked to having more relapses. They also showed that getting extra vitamin D reduced the number of relapses. But not all studies have shown these two things.

Talk to your neurologist about this. Many give their patients vitamin D supplements as it does no harm and may help with their MS.

What isn't a relapse?

It’s often difficult, especially in the first few years, to know what is and what isn’t a relapse. It's not uncommon to experience some ‘on-off’ symptoms even during remission – for example, fatigue or balance problems.

New symptoms can be shocking or distressing at any time, but not every symptom will be a sign that a relapse is beginning. Over time, you will get more confident in understanding the symptoms as you get to know your MS.

Don’t put everything down to MS. This can stop you exploring everything that could be causing a new symptom. It's possible that it's nothing to do with MS and needs to be checked out.

Managing relapsing remitting MS (RRMS)

Managing symptoms

There are treatments and ways of managing symptoms which can help you deal with many different MS symptoms.

Find out more about managing symptoms

Managing relapses

Find out about strategies and treatments for managing relapses

Disease modifying therapies

Disease modifying therapies (DMTs) can reduce the number of relapses you get and slow down the rate at which disability happens to you. They work better the earlier you start taking them. Damage caused by MS builds up over time, so the sooner you begin treatment, the less damage will have built up before treatment starts to take effect.

Official guidelines recommend that everyone with MS has a review with their specialist at least once a year. You should be deciding together with your specialist what your treatment plan is. Treatment with a DMT can keep your number of relapses as low as possible and slow down the damage building up that can lead to permanent disability.

Explore your DMT options with our tool

The move to secondary progressive MS

Most people with relapsing remitting MS eventually develop secondary progressive MS. How soon this happens varies widely from person to person. Before disease modifying therapies (DMTs) came along, it took around 20 years on average.

But thanks to today's MS drugs this is changing:

  • fewer people are likely to go on to secondary progressive MS
  • and for people who do, it could take longer to happen

Read more about secondary progressive MS

How many people have relapsing remitting MS (RRMS)?

There are roughly 1.3 million people worldwide who have relapsing MS out of 2.3 million with any type of MS. In the UK, there are more than 150,000 people living with MS. When they were first told they had MS, 85% of them were diagnosed with the relapsing remitting type.

Diagnosing relapsing remitting MS (RRMS)

MS is complex and can cause many different symptoms, so it’s not easy to diagnose. It’s hard to pinpoint exactly when MS begins, and the early signs and symptoms are different for everyone. It’s not uncommon for a diagnosis to take several months, and frustratingly it can take even longer. A range of other possible causes need to be explored and many different tests need to be carried out.

Read more about diagnosing MS