Some MS flare-ups may not require treatment and will resolve on their own. Others may require medications and other therapies. Avoiding triggers may help prevent flare-ups.

Multiple sclerosis (MS) is a condition that affects the central nervous system (CNS). MS can cause a wide range of symptoms, from numbness in your arms and legs to paralysis (in its most severe state).

Relapsing-remitting MS (RRMS) is the most common type of MS. With RRMS, symptoms can worsen during episodes and then improve when the episodes resolve. A return of symptoms can be classified as a flare-up.

A flare-up is an episode that causes new MS symptoms or worsens old symptoms. A flare-up may also be called:

  • an attack
  • a bout
  • an episode
  • an exacerbation
  • a relapse

Read on to learn more about MS flare-ups and how to treat and possibly prevent them.

To understand what an MS flare-up is, you first need to know the symptoms of MS. One of the most common symptoms of MS is a feeling of numbness or tingling in your arms or legs.

Other symptoms can include:

  • pain or weakness in your limbs
  • vision problems, such as double vision
  • loss of coordination and balance
  • dizziness
  • fatigue

In serious cases, MS can also lead to vision loss. This often occurs in just one eye.

People experience flare-ups differently. Symptoms can vary each time one occurs.

Sometimes they’re mild. Other times, symptoms can be so severe they make it difficult to function. There can be one symptom or more than one, depending on how the CNS is affected and how many areas of the CNS are involved.

Symptoms of flare-ups include:

  • weakness in the legs or arms
  • blurred vision or eye pain due to optic neuritis, which is an inflammation of the optic nerve that affects and impairs vision
  • balance problems or dizziness
  • severe fatigue
  • issues with memory or concentration
  • numbness
  • tingling or a feeling of pins and needles
  • slurred speech or trouble swallowing
  • bladder issues, including incontinence or a frequent need to urinate

It can be difficult to tell whether the symptoms you’re having are a flare-up or regular symptoms of your MS.

Symptoms only qualify as flare-ups if they:

  • occur at least 30 days after an earlier flare-up
  • last for 24 hours or longer
  • aren’t related to infection or another medical cause
  • aren’t present in between flare-ups

Some of your symptoms can be present all the time and may worsen during a flare-up, such as fatigue, trouble concentrating, or bladder issues. And you might only have certain symptoms during your flare-ups.

According to some research, most people with RRMS experience flare-ups throughout the course of their disease.

Flare-ups are caused by inflammation in the CNS that damages the myelin, a fatty substance that protects the portion of the cell called an axon.

Axons carry messages to other parts of the body, and the protective myelin helps speed nerve transmission. When the myelin is damaged due to inflammation, those messages are slowed or disrupted. This causes MS symptoms and flare-ups.

There’s no way to completely cure MS, but MS disease-modifying therapies (DMTs) can help reduce or prevent flare-ups.

There are ways to avoid the triggers that may prompt them, too.


According to a 2015 research review, stressful life events, like those with work or family life, can increase the occurrence of MS flare-ups. The review notes that the association between stress and flare-ups was strongest in studies using self-reported diaries.

Keep in mind that stress is a fact of life. But you can take steps to reduce it. You can help lower your stress levels by:


According to a 2015 research review, common infections, such as the flu or a cold, can trigger MS flare-ups.

While upper respiratory infections are common in the winter, you can take steps to reduce your risk, including:

Urinary tract infections (UTIs) can also trigger MS flare-ups. Because of bladder issues, UTIs are common in people with MS.


Some people have concerns about surgery and anesthesia bringing on flare-ups. According to the National MS Society, neither will bring about a flare-up.

Anesthesia is generally considered safe for people who live with MS. People with advanced MS and respiratory problems have a higher risk of complications from anesthesia, but not flare-ups. (However, complications are rare.)

There have been some studies suggesting a possible link between having had tonsillectomy and later getting an MS diagnosis, but it’s not certain that there’s any specific cause and effect.

It’s important to remember that this potential link involves risk of disease onset, not of a flare-up of symptoms.


Concerns about vaccinations have become ubiquitous in recent years. People living with MS may have additional concerns, including whether vaccines bring on flare-ups or worsen MS.

Research has shown that vaccines don’t worsen MS. Studies have looked at all kinds of vaccines, from seasonal flu vaccines to hepatitis B and even the current COVID-19 vaccines.

The National MS Society has an entire page on its website dedicated to vaccines, including precautions to take in certain cases, including:

  • not getting a vaccine while you’re experiencing a flare-up
  • avoiding live-virus vaccines if you’re taking certain kinds of medication

As always, discuss all medications with your doctor before making any changes.

Other risk factors

Older people may be more likely to experience flare-ups, according to a 2019 research review.

Men and women are also prone to different types of flare-ups.

Other risk factors for flare-ups that researchers have identified include:

  • not taking DMTs
  • heat exposure
  • fatigue
  • serum levels of vitamin D
  • smoking
About pseudoexacerbations

Pseudoexacerbations are worsening MS symptoms that aren’t caused by new central nervous system (CNS) inflammation that damages the myelin.

During a pseudoexacerbation, symptoms that may have been present in the past will briefly worsen or reemerge. These symptoms are temporary. Potential causes include:

  • an illness or infection, especially a urinary tract infection (UTI)
  • depression or anxiety, which are often brought on by stress
  • exhaustion
  • exercise
  • an environment that’s too warm

Once the reason for the pseudoexacerbation is found and treated, the symptoms usually resolve within 1 day.

To qualify as a flare-up, symptoms must last for at least 24 hours.

The duration of a flare-up can be different for each person and for each flare-up. Flare-ups may only last for a few days, but sometimes they can last for weeks and even months at a time.

Flare-ups can happen with little to no warning. However, there are important steps you can take that may help prevent them. Maintaining overall health is important for everyone, but it’s especially necessary for people living with MS.

Much of what you can do involves preventing infections. To do that, eat a nutrient-rich and balanced diet.

If you smoke, get help to quit. Smoking increases the chances of chest infections and respiratory infections, which can bring on flare-ups.

If you’re prescribed DMTs, be sure to take them as directed. Missing doses can cause problems. If you have concerns about your DMTs or any associated side effects associated, speak with your doctor to see what other options may be available.

Make sure you have a support network and people who can help if you need it. Talk with your family and friends about how you’re feeling.

Some MS flare-ups may not need to be treated. If symptom flare-ups occur but don’t affect your quality of life, many doctors will recommend a wait-and-see approach. The issues may clear up on their own.

Some flare-ups cause more severe symptoms, such as extreme weakness, and require treatment. Your doctor may recommend:

  • Corticosteroids. These medications can help bring down inflammation in the short term.
  • H.P. Acthar gel. This injectable medication is generally used only when corticosteroids haven’t been effective.
  • Plasma exchange. This treatment replaces your blood plasma with new plasma. It’s used only for very severe flare-ups when other treatments haven’t worked.

If your flare-up is very severe, your doctor may suggest restorative rehabilitation as you begin to regain strength. This treatment may involve:

  • physical therapy
  • occupational therapy
  • treatment for problems with speech, swallowing, or thinking

Since flare-ups can be different for each person, recovery will also be different.

Consider your lifestyle and how active it normally is. Things may need to change for you to recover well.

Take time off from work if you can, and get assistance around the house if possible. If your recovery looks like it may be lengthy, consider professional home help, such as an MS nurse or assistance from social service organizations.

Flare-ups may bring up emotional issues as well. Anxiety and depression may get worse. Talk with your doctor about whether therapy or similar mental healthcare support is a good idea for you and even for members of your family.

Different kinds of approaches may also be useful. This can include physical and occupational therapy, new medications, and mental health therapy as mentioned above.

Your doctor will help determine the right kinds of specialists for you so that your recovery is as easy as possible.