Relapses in MS

Relapses can be difficult to understand. Knowing  whether or not the symptoms you are experiencing are due to a relapse is important. Below

What is a relapse?

What is a pseudo-relapse? 

What happens in a relapse? 

What should I do if I think I am having a relapse? 

Can relapses be treated?

Can I reduce my risk of relapse?

What is a relapse?

A relapse is a significant worsening or a re-occurrence of a symptom, or a group of symptoms, lasting for more than 24 hours in the absence of infection or a change in core body temperature.

Relapses occur when inflammatory cells attack the myelin of specific nerves, interfering with the job the nerve normally does. For example, inflammation of the optic nerve may cause vision problems. Relapses usually take a few days to develop and can last for days, weeks or months, varying from mild to severe. Remission occurs when the inflammation subsides and symptoms settle down.

There are a number of terms used interchangeably to describe a relapse, this includes ‘flare-ups’, ‘attacks’ and ‘exacerbations’.

What is a pseudo-relapse? 

A pseudo-relapse is the appearance, reappearance or worsening of symptoms that is brought on by other factors. There can be many reasons why symptoms may temporarily worsen, these include:

  • Infection – having infections can cause symptoms to temporarily worsen. Usually, once the infection has cleared up so too do the symptoms. Taking care of yourself if you experience an infection is important. Discuss any concerns with your GP who may prescribe antibiotics if required. A severe infection can trigger a relapse so taking good care of yourself is important.
  • Extremes of temperature - (either hot or cold) – some people find that their symptoms become worse if they are too hot or too cold. If so, maintaining a comfortable temperature may help.
  • Stress – Symptoms can worsen or feel harder to manage if you’re feeling stressed or under pressure. Finding ways to manage or reduce stress may help. MS Ireland have MS Wellness resources which may help here.
  • Tiredness – Symptoms can increase due to tiredness or overexertion. Managing fatigue is important. MS Ireland have a webinar on fatigue management which is available here.
  • Periods – some people living with MS can experience temporary worsening of symptoms before or during their period.
  • Deconditioning – some people may find their symptoms worsen if they become inactive, are on bedrest or have a sedentary lifestyle.

What happens in a relapse? 

A relapse happens when there is an acute attack of the central nervous system (CNS). The nerves in the CNS, which consists of the brain and spinal cord are coated by myelin. This acts as a protective layer, assists with nourishment and also helps the signals that are passed along the nerves to travel. In MS, the immune system attacks this myelin coating. It can cause inflammation and demyelination, where the myelin is damaged or stripped away. The areas that are damaged are known as lesions. This can impact the ability of the nerves to pass along messages. The messages may pass more slowly, be interrupted or completely blocked. This can result in a new or worsening symptom – a relapse. The symptom you experience depends on the part of the brain or spinal cord that has been affected. 

Relapses can last for varying periods of time from days to months. Once the inflammation reduces, myelin may repair (remyelination). The messages that were slowed, interrupted or blocked can now pass along the nerves more effectively. They may not return to the same speed as before and so some symptoms may be persistent.

Some lesions can occur without a relapse. This can happen if demyelination occurs in a part of the brain or spinal cord that does not lead to symptoms. It is also possible for the brain to quickly re-route messages around areas that are impacted. These lesions can be seen on MRI scans.

What should I do if I think I am having a relapse?

Relapse can be a sign that your disease is more active so it is important to make contact with your healthcare team if you think you are having a relapse, no matter how mild the symptom may be. This is important as your healthcare provider can help you to understand whether it is a relapse and can explore of there is activity. Activity is a term used to describe either a clinical attach or when the MRI shows evidence of activity on a scan.

Your healthcare provider may ask you about the symptom. You may be asked questions including:

  • What is the symptom?
  • When did the symptom start?
  • Which part of the body is it affecting?
  • Is the symptom persistent or does it come and go?
  • Have you recently been unwell or had an infection?
  • What medications are you currently taking?
  • Has there been any recent change to the medication you are taking?

Ultimately, your healthcare team is in place to support you and can help you to identify what is and isn’t a relapse. You do not have to decide this for yourself. If you think you are experiencing a relapse or have any concern about symptoms, then you should make contact with your MS nurse or neurologist so they can provide you with individualised support and advice.


Sometimes it can be difficult to remember the symptoms you have experienced between conversations with your neurology team.  The table below may be useful in keeping track of the symptoms you experience. 

You can print it and fill in whenever you need to make note of a symptom.

Can relapses be treated?

Your healthcare team will help to determine if what you are experiencing is a relapse. They will discuss this with you and may recommend treatment for the relapse if they feel it is necessary. It is important to note that not all relapses need treatment. The symptoms of a relapse will typically resolve on their own.



In some instances, where a relapse is having a significant impact on your life, your healthcare team may recommend taking a course of steroids. Typically, this will be discussed with you. Steroids can speed up recovery but they will not affect the outcome of the recovery. They are sometimes be administered as tablets or through an intravenous infusion in the hospital. Information on steroids can be found here


Other interventions

Sometimes interventions such as medications to treat MS symptoms, physiotherapy, occupational therapy, speech and language therapy or neuropsychology may be put in place to help support you with a relapse.

Your healthcare team will help to decide the best course of action and make referrals as appropriate.

Can I reduce my risk of relapse?


While relapses are unpredictable and spontaneous, maintaining a generally healthy lifestyle may help to avoid potential triggers that may increase relapse rate.

  • Smoking - research indicates that smoking increases the risk of relapse. Therefore, avoiding smoking may help to reduce your chance of experiencing relapse.
  • Severe infections - can also trigger relapse so it is important to discuss any infection you may have with your healthcare team so any necessary measures can be taken to help mitigate the infection worsening. Vaccinations may be recommended, please speak to your healthcare team for individualised advice.
  • Healthy diet and exercise – eating a well-balanced diet and getting enough exercise will help you to maintain your general health.
  • Stress – some studies have indicated that long periods of stress can increase relapse risk though other studies are not as clear on this. Either way, managing stress can help to achieve greater overall general health which can leave you in the best position to recover in the event that you do experience a relapse. 
  • Disease-modifying treatments – disease-modifying treatments can help to reduce relapse rates as well as the severity of relapses. It is important to your treatment plan if you have been prescribed a disease modifying therapy. Taking any such treatment as prescribed is important. If for any reason you experience reluctance in taking the treatment or you repeatedly forget to take it as prescribed, you should discuss this with your MS Nurse or neurology team. 

Watch our Relapse webinar with consultant Neurologist Dr Hugh Kearney.

Useful Resources

In December 2016, MS Ireland and Novartis developed an infographic explaining MS relapses. The infographic was developed in consultation with a group of people with MS and healthcare professionals. You can find it here

MS & Me blogger Joan Jordan discusses her experiences of relapse in this blog

MS & Me blogger Willeke Van Eeckhoutte shares her relapse experiences here


For more information see