What is an MS relapse?

An MS relapse is the clinical presentation (symptoms you experience) when there is a new episode of inflammatory activity in an area of your brain or spinal cord. Depending on where the area (or areas) of inflammation is, will lead to the symptom (or symptoms) you may experience.

Relapses can be mild, or severe enough to interfere with your usual everyday life. No two relapses are the same, and symptoms will vary from person to person and from one relapse to another.

Some people call MS relapses by different names, which can be confusing. Some other terms used for relapse are: exacerbation, flare up, attack.

To be classified as a true clinical relapse:

• Symptoms must last at least 24 hours (however relapse symptoms generally last for days, weeks or even months)
• There must be new symptoms (or old symptoms must be worse than they have been)
• Symptoms must occur at least 30 days from the start of the last relapse
• There must be no active infection
• There must be no other explanation or trigger for the symptoms (See triggers below for more information on what these could be)

In practice, even for professionals working in the field of MS, it can be difficult to determine if some symptoms are a true relapse or not.

What can I expect from an MS relapse?

In an MS relapse, symptoms usually develop over a few hours to a few days before reaching their worst. They then might stay at this level for a few days before starting to improve. It is then expected that recovery will happen over a few weeks, but it can take several months.

Your symptoms may fully resolve, or you may be left with some symptoms from a relapse. The MS Society states that 'around half of all relapses may leave some lingering problems' Relapsing Remitting MS (RRMS) - MS Relapse Signs | MS Society

Even if your symptoms fully resolve, areas of damage from a relapse (episode of inflammation) may still be present in your brain or spinal cord and may remain visible on an MRI scan.

What isn't a relapse?

It is very common for the symptoms that you have had previously to come and go. This is because your nervous system is continually dealing with (compensating for) the damage caused by previous MS relapses, so that you don't always experience the symptoms at all, or as badly as you have had them in the past.

Your nervous system can often manage this quite successfully while it is only your MS symptoms that it is having to juggle. As soon as it has to juggle other things, (see triggers below) it becomes too much for your nervous system, so your 'MS symptom juggling balls' may get dropped temporarily and your MS symptoms may return.

Old symptoms that come back less frequently may be because you don't have triggers (or are managing the triggers well), or because they need a more significant trigger to make them appear

When you are first diagnosed with MS, it can be difficult to know whether your symptoms are a relapse or not. Over time, you'll learn what's normal for you with your MS and symptoms.

We usually describe the return of old symptoms, because of one or more triggers, as 'decompensation' or 'pseudo-relapse', but it can also be called 'ghosting' or 'flare-up'.

Decompensation isn't due to new inflammatory activity and damage and doesn't mean that your MS has become out of control.

It also means that generally once the trigger is removed, it would be expected that the symptoms would return to their previous level.

Triggers for symptoms worsening or coming back

Anything that affects you or your body can be a trigger.

This could be something happening to your body or something affecting how your body usually functions.

Here are some examples of things that can be a trigger for worsening of MS symptoms, (but is not a complete list):

• Infection (e.g. urinary tract or chest infections, colds, flu, Covid, dental infection)
• Constipation
• Broken skin or skin irritation (including pressure sores or other wounds)
• Pain
• Another condition (such as kidney stones, irritable bowel syndrome, arthritis)
• Stress or anxiety
• Low mood or depression
• Over-doing things (being too busy/not having sufficient rest)
• Lack of (or disturbed) sleep
• Menstrual period or menopause
• Hot (or cold) weather

What causes relapses?

Relapses often happen for no reason, but we know that there are some things that make them more likely.

Not treating your MS

Disease modifying drug (DMD) treatments can reduce how many relapses you have and how bad they are. They make the biggest difference in your likelihood of having MS relapses. See Disease Modifying Drugs (DMD) for more information about these treatments.

Smoking

People who smoke are likely to have more relapses than people who don't smoke.

Smoking has also been found to reduce the effectiveness of some of the MS disease modifying drugs. This means they may not protect you from MS relapse as well, if you smoke. More information about smoking and MS can be found on the MS Trust website Smoking | MS Trust and the MS Society Smoking and MS | MS Society.

Infection

Severe infections can trigger a relapse. It is therefore important that you see your GP if you feel you may have an infection to get assessed and treated if indicated.

It is also advised that you have any immunisations recommended as part of national vaccination programmes or by your GP, e.g. Covid, Shingles, Flu vaccines.

Other

There are other things that are linked with an increased risk in relapse but there is not as much research evidence to back these up. These include:

• Stress
• Low vitamin D levels

This means that leading as healthy a lifestyle as possible is important in reducing the risk of MS relapse.

Different types of MS relapse

• Sensory - reduced or altered sensation (feeling)
• Motor - weakness
• Cognitive - affecting thinking processes
• Optic neuritis - affecting the optic nerve which will give visual symptoms (Vision)
• Mixed relapse - where you have more than one of these types

Steroids (Methylprednisolone)

Steroids can be used to treat relapses, but not all relapses need treatment with steroids.

Steroids work on the inflammatory process and not the MS damage itself. This means steroid treatment won't affect how well you recover from a relapse, it only speeds up recovery time.

We also know from evidence that steroid treatment in MS works better in some types of relapses than others.

Steroid treatment would only be suggested should your relapse be particularly disabling and a clinician feels that it is required.

If steroid treatment is suggested for you, the NICE (The National Institute for Health and Care Excellence, MS Guideline: Recommendations | Multiple sclerosis in adults: management | Guidance | NICE) recommended treatment course is:

• Methylprednisolone tablets - 500mg daily for 5 days

Steroids are not helpful in decompensation/pseudo-relapse as there isn't any inflammation present for the steroids to work on.

What to do if you think you may be having a relapse

If you think you may be having a relapse:

• Keep a diary of your symptoms as this is useful to remember dates and exactly what is happening and when
• f your symptoms last for more than 24 hours, call or email the MS Service Helpline on 0300 019 2362 or This email address is being protected from spambots. You need JavaScript enabled to view it. and leave a message stating that you think you may be having a relapse, and leave a brief description
• You will be placed in the next available helpline duty clinic with one of the MS practitioners. This is likely be the same day or next working day (depending on when you contact the service)
• The practitioner will go through some questions, which will include going through possible triggers. It would be useful for you to go through possible triggers before you speak to the practitioner (see Triggers section above)
• The practitioner may offer advice over the phone or may suggest that you attend an Acute MS Symptom Clinic at Poole Hospital

If you feel you need urgent medical advice, please contact 111. If you feel your condition is life threatening, please call 999 or go to an Accident & Emergency Department.