Signs of an MS Flare

Living with multiple sclerosis (MS) means dealing with flares. Flares occur when symptoms worsen for at least 24 hours. To be considered a flare, it also must occur 30 days or more after the last attack.

We wondered what cues your body gives you about flares. We asked our community on Facebook, “How can you tell that you are experiencing an MS flare?” We got more than 250 responses, so it is clear that there are many ways flares affect you.


Many of you experience numbness or tingling in your body. This often occurs in the arms and legs. You have less sensation in the affected body part. The numbness can make it difficult to balance, walk, hold things, or write.

“Numbness, usually starting in my hand(s) and spreading out from there.”

“When I flare up, the right side from my cheek all the way down to the toes goes numb.”

“Tingling in my toes.”

“My normal right side numbness will extend from just my lower leg all the way up to my head.”

“My skin goes numb.”

Difficulty moving

Movement often becomes challenging when you begin to flare. You may bump into things, move slowly, or drag your feet. Your legs and arms feel heavy and leaden. Everything takes more time. 

“Mine starts in my arms and legs. They get heavy to the point that I can’t move well.”

“I walk like a drunken sailor.”

“It feels like I’m walking in cement.”

“Every step feels like you are knee-deep in tar.”

Fatigue and brain fog

Bone-weary exhaustion indicates a flare for many of you. You need extra sleep. You have trouble focusing. Your body cannot keep up with your regular routine. 

“Increased fatigue and cognitive fog.”

“I get confused, and I just don’t function well at all.”

“Excessive fatigue and insomnia.”

Cognitive function

Several people mentioned declining cognitive function during a flare. Cognitive function is different from brain fog. Brain fog is feeling sluggish in your thinking. Your words and thoughts may be present but hazy. Getting them out can feel like pulling them through molasses.

Cognitive function describes your communication ability. When it declines, words disappear or change. You may not be able to follow conversations. Different words come out of your mouth than what you think you said.

“I can’t speak the words I’m thinking.”

“Can’t think straight or remember simple words.”

“I stutter like crazy and can’t find my words.”

“I start to lose my speech.”

Bladder control

Struggling with your bladder is another common flare sign. Many of you experience loss of bladder control and increased urgency to urinate. Repeated bladder problems can lead to urinary tract infections (UTIs).

“Bladder spasms.”

“Bathroom problems.”

“When you get a UTI.”

“I had a really hard time with controlling my bladder.”

Headache and migraine

Headaches and migraine symptoms are another flare indicator. Head pain persists as a flare takes hold. It is difficult to function through headaches and migraine aura symptoms. 

“Worst headache you can imagine!”

“Headaches that won’t go away.”

“Thanks to everyone who mentioned migraines!! I have had these since age 13 and can usually figure out what made my migraine flare up. Never thought of my MS.”

Sensory sensitivity

Many of you notice an increased sensitivity to sound and light. Noises that otherwise are not bothersome trigger reactions. Bright lights make it hard to see. 

“The slightest noise set up a migraine.”

“Loud noise gives me anxiety.”

“Eyes become blurry and sensitive to light.”


1. Managing Relapses. National Multiple Sclerosis Society. Available at Accessed 8/18/2022. 

2. Numbness or Tingling. National Multiple Sclerosis Society. Available at Accessed 8/18/2022.

3. Fong T. Brain fog: Memory and attention after COVID-19. Harvard Medical School. Available at Accessed 8/18/2022. 

4. Cognitive Changes. National Multiple Sclerosis Society. Available at Accessed 8/18/2022.

5. MS Signs and Symptoms. National Multiple Sclerosis Society. Available at Accessed 8/18/2022.

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  • Christine Weselcouch says:

    There is no mention of vision problems here! I don’t know if they are considered a flare, but some days are worse than others. My two eyes cannot focus, and I need to close one to be able to see!

  • Hope H says:

    In was recently hospitalized with stroke symptoms. I could not walk or voluntarily move; I could not talk; I could comprehend some or most of what was being said to me and some of the things that happened to me I don’t remember. My daughter was there or I wouldn’t know a lot of things happened. MRI’s ruled out a stroke and an TIA. Those doctors are now saying “I had a reaction of old MS or other neurologic reaction which has resolved.” Is this a common flare? Incidentally, I was at physical therapy when this occurred, and my therapist was so worried, she called the ambulance, which took me to a stroke center hospital. The doctors on the stroke team must have thought “stroke” also, because they administered the “stroke buster” med, TPA (I think that was the name), with all the side effect warnings.
    I am having trouble seeing my neurologist with out waiting until my regular appt, in December. That doesn’t sound like such a great idea

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