Practical patient questions

What to Do If You Think You Have Had an MS Relapse

Published April 2026

A relapse can be alarming — especially if it is your first, or if this one feels different from others you have had before. Knowing what a relapse actually is, and what to do when you think you are having one, can help you act more quickly and feel more prepared when you speak to your care team. This guide covers the key steps: how to recognise a relapse, what to do in the first few days, what to record, and how to prepare for the conversation with your neurologist or MS nurse.

What is an MS relapse?

A relapse — also called an attack, exacerbation, or flare — is the appearance of new MS symptoms, or a significant worsening of existing symptoms, that lasts more than 24 hours and is not caused by illness or a rise in body temperature.

The MS Society describes relapses as periods when symptoms flare up, usually developing over hours or days, before stabilising and then often partially or fully recovering over weeks or months.

Not every symptom change is a relapse. Feeling worse temporarily due to heat, infection, or exhaustion is known as a pseudo-relapse — it can feel similar but usually resolves quickly once the trigger is addressed. The key distinction is whether symptoms are new, significantly worsened, and lasting beyond 24 hours without an obvious cause like illness or overheating.

How do you know if it is a relapse?

MS Trust describes relapses as symptoms that suddenly appear or become significantly worse, usually developing over hours or days. Common signs that something may be a relapse include:

• –A new symptom you have not experienced before
• –An existing symptom that has returned more severely or for longer than usual
• –Symptoms that developed over hours or days (not suddenly in seconds)
• –Symptoms that have persisted for more than 24 hours
• –No obvious trigger such as heat, illness, or extreme tiredness

If you are unsure whether what you are experiencing is a relapse, it is always worth contacting your MS team. You do not need to be certain before reaching out.

What to do in the first 24–48 hours

Rest.Relapses place significant demand on the body and nervous system. Rest — both physical and cognitive — supports recovery. This does not mean complete bed rest, but scaling back activity where possible is helpful.

Treat any underlying illness. If you have an infection (particularly a urinary tract infection, which is common in MS and can cause significant symptom worsening), treating it may resolve or reduce what seems like a relapse. MS Society guidance highlights the importance of ruling out infection before assuming a relapse is occurring.

Avoid heat.Heat can worsen MS symptoms significantly during a relapse. Staying cool — through cool showers, cold drinks, or air conditioning — can help manage symptom intensity.

Write down what is happening. Note the date symptoms started, which symptoms appeared or worsened, and how severe they are. This record is valuable whether the episode turns out to be a true relapse or not.

Contact your MS team. You do not need to wait to see whether things improve before calling. Your MS nurse or neurologist can advise on next steps, assess whether treatment is appropriate, and arrange any necessary tests.

What to record during a relapse

A clear record helps your care team make better decisions about treatment and gives you an accurate picture to refer back to later. Try to note:

• –When it started — the date and approximate time symptoms first appeared or changed
• –What symptoms you have — be specific: not just "my leg is weak" but "I cannot reliably lift my left foot when walking, which started Tuesday morning"
• –How severe each symptom is — a simple 1-10 scale is helpful for tracking whether things are improving, staying the same, or getting worse
• –What has changed since it started — is it getting better, staying the same, or worsening?
• –Any possible triggers — recent infection, illness, or significant heat exposure
• –How daily life is affected — what can you not do now that you could do before?

You do not need a detailed medical account. A short dated note — written as things happen — is more useful than trying to reconstruct the timeline later from memory. See our guide on what makes a good MS symptom tracker for practical approaches.

When to contact your MS team

Contact your MS nurse or neurologist if:

• –You have new or significantly worsened symptoms lasting more than 24 hours
• –You are unsure whether what you are experiencing is a relapse
• –Symptoms are affecting your ability to function, work, or care for yourself
• –Symptoms are getting worse rather than stabilising

Most MS centres have a relapse helpline or a way to contact your MS nurse directly. If you are unsure who to call, your GP can also advise or refer you. MS Trust recommends contacting your care team as early as possible during a potential relapse, as some treatments are most effective when given soon after symptoms appear.

What happens at a relapse assessment

When you contact your MS team, they will typically want to:

• –Understand your current symptoms and when they started
• –Rule out infection or other causes (a urine test is common)
• –Assess how significantly the relapse is affecting your function
• –Discuss whether a short course of high-dose steroids is appropriate

Steroids (usually methylprednisolone) can speed up recovery from a relapse, though they do not change the long-term outcome. Your team will discuss whether the severity of the relapse makes treatment worthwhile, as steroids have side effects and are not recommended for every relapse. National MS Society guidance notes that the decision to treat with steroids depends on how much the relapse is affecting daily function.

After the relapse: what to track

Recovery from a relapse can take weeks or months, and does not always follow a predictable pattern. Keeping notes during recovery helps you and your care team understand how things are progressing. After a relapse, it is worth tracking:

• –Which symptoms improved, and when
• –Which symptoms are still present or only partially resolved
• –How your daily function has changed compared to before the relapse
• –Whether fatigue has increased — this is common after a relapse and can persist even after other symptoms improve
• –Any new patterns or limitations that have emerged

This information is also valuable at your next appointment. If your neurologist asks how you recovered, having a record is far more useful than trying to reconstruct it from memory months later. See our guide on preparing for your next MS appointment.

My MS Path’s check-in covers relapses as part of its structured review — including whether you had one, how it affected you, and whether you have fully recovered. Start the free check-in.

This article is for general information and does not replace medical advice. Speak to your healthcare provider about any concerns.