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Is it an MS Relapse or Pseudoexacerbation?

The symptoms of MS – muscle weakness, tingling, muscle spasms, or vision difficulties – suddenly appear again: but is it a relapse or a pseudoexacerbation?

Pseudoexacerbation sounds like it’s a fake or made-up condition, but the symptoms are very real. Pseudoexacerbations of MS are a flare of symptoms that have been experienced before, and they usually only last about 24 hours.1 Unlike a relapse, pseudoexacerbations are not a worsening of the disease, and they are not related to new inflammation in the central nervous system.

In most people with MS, pseudoexacerbations are triggered by heat, such as a fever, hot bath, exercise, or spending too long in the sun. Increases in body temperature as little as a half a degree affect the nervous system, causing it to not work as efficiently and bringing up symptoms of an old inflammation. The symptoms from a pseudoexacerbation go away once the body temperature returns to normal.

Relapses are symptoms that are new or worsened symptoms that last for more than 24 hours. Relapses are also characterized by length of time – they do not occur within 30 days of a previous relapse. Also, the symptoms of a relapse cannot be explained by any other cause. In contrast, the symptoms experienced during a pseudoexacerbation may be explained by exposure to heat or an infection in the body.

What can cause a pseudoexacerbation?

Common causes of pseudoexacerbations include:

  • Fever due to a urinary tract infection (UTI) or sinus infection
  • Spending an excessive amount of time in the sun, such as at the beach or in the backyard
  • Vigorous exercise, especially combined with warm weather
  • Taking a hot bath or spending time in a hot tub

Some women find that hormonal changes, such as those that occur during the menstrual cycle, may set off a pseudoexacerbation. Rarely, people with MS are sensitive to cold temperatures, and for them, getting too cold can cause a flare of symptoms.

When a pseudoexacerbation happens, what should you do?

If you experience a flare of symptoms, take immediate action to care for yourself, getting as safe and comfortable as possible. If you’ve gotten overheated, move to a cooler environment, such as moving out of the sun and into an air-conditioned room. Drink cool water, and try to calm your mind and body with some slow, deep breaths. With pseudoexacerbations, symptoms go away within 24 hours.

If your symptoms last longer than 24 hours, contact your doctor. Depending on your overall health, your symptoms and how long they have lasted, your doctor may prescribe corticosteroids. However, corticosteroids do have risks associated with their use, including upper gastrointestinal bleeding, increasing the risk of osteoporosis, and possibly causing emotional changes, so doctors don’t always recommend them as a cure-all.

How can pseudoexacerbations be prevented?

While not all pseudoexacerbations can be avoided, there are several lifestyle practices that may reduce the chance of getting one, including:

  • Avoid overexertion, such as strenuous exercise or yard work, particularly during hot days
  • Limit exposure to hot environments, like saunas, hot tubs, or being outside during the hottest part of the day
  • Practice good hygiene (like frequently washing hands) and avoid others who are sick to reduce your risk of developing an infection
  1. National Multiple Sclerosis Society. Accessed online on 2/17/17 at


  • Bettybeem
    3 years ago

    I have found that true exacerbations have a definite beginning. I may wake up and know immediately. Once I was doing water aerobics, suddenly I had no sensations below the waist. Another time I was waiting in line on a December morning, without warning, my right side went totally numb. Twice in the summer, what I hoped were pseudoexacerbations were actually the real things.

  • Pam
    3 years ago

    it seems none of my events are a relapse. vision is messed up, blurry spots, prisim effect, muscle spasms, .. none of that is a relapse. I get real confused about what is and is not ms related.. so ive quit telling them. spent the day in er with steroid infusion, morphine drip because my arms and upper body wouldn’t quit with the spasms. that lasted about 2 weeks. and my neuro said it was not a flare.

  • Carol
    3 years ago

    I’ve had a relapse since the beginning of this month. I was going to go to the neurologist’s office, but then I kept on worrying about those stereoid ivs and stayed away. So, here I am still with the darn irritating symptoms. It’s been such a long time since I had a relapse and I can’t remember how long that one lasted. I recently went to neurologist because of my back pain. My husband was real gung-ho, great, he doesn’t have to go through this. Those epidurals used to work, but then they didn’t so I’m afraid that a newer neurologist with a different angle is going to have different luck than the others.

  • MsTrivette
    3 years ago

    I get them in the summer. I’ve had optic neuritis, so when I get too hot during the summer months, my vision will blur and I will lose some of my color vision. Before I knew about pseudo exacerbations, I thought I was having attacks.

  • minkoala
    3 years ago

    Pseudoexacerbation is what my neurologist says all my symptoms are now and does not treat me for anything now. Just because I don’t want any MS DM treatments

  • Dora
    3 years ago

    Every single time that I get a UTI, I end up with a pseudoflare. Actually, I don’t get the typical symptoms for a UTI. I know that I’m in trouble when I can hardly walk, have major fatigue, etc. I take a daily antibiotic as a preventative, as well as 8400 mg twice a day of cranberry herbal supplement..If I alter anything, like stop taking the daily antibiotic, within two weeks I will have a UTI.

  • Christina Hegarty PT, DPT moderator
    3 years ago

    Hi Dora,
    I’m sorry to hear about your issues with UTI’s and the subsequent psuedoflares. I’m glad you have found a way to help you prevent them though. Thank you for sharing with us! Please know we are here for you anytime!
    Take care,
    Christina, Team

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