What Is MS Pseudo-Exacerbation?

Telling the Difference Between a Real and "Fake" Attack

You are not alone if you have ever felt your MS symptoms suddenly arise or increase in intensity. Perhaps you felt your legs go numb or an overwhelming cloud of fatigue wrap around you.

While it's normal to be worried, even panicked, that you are experiencing an MS relapse or exacerbation, this is not necessarily the case. You may be experiencing a pseudo-exacerbation, which is a "false" MS exacerbation or relapse.

While distinguishing an MS exacerbation from a pseudo-exacerbation can be tricky, it's an important first step. This is because a pseudo-exacerbation does not require treatment with steroids like Solu-Medrol and it does not affect a person's long-term disease course.

What Is MS Pseudo-Exacerbation
Verywell / Cindy Chung  

Distinguishing a Pseudo-Attack

Multiple sclerosis (MS) exacerbation (also known as a relapse attack, bout, or flare) occurs when a person experiences either new MS symptoms or a worsening of old symptoms. For example, a person may experience new muscle weakness in their legs or worsening balance problems.

Four Features of Pseudo-Exacerbation

  • No new MS damage is occurring
  • Triggered by an outside factor
  • Symptoms are reversible
  • Lasts less than 24 hours

On the contrary, with an MS pseudo-exacerbation, a person experiences a temporary increase in their symptoms. This temporary increase in symptoms (such as fatigue or tingling in their arms and legs) is brought on by some sort of outside trigger such as heat or stress. The temporary increase in symptoms with a pseudo-exacerbation implies there is no MS-related inflammation going on in the brain or spinal cord—although, it can certainly feel like it.

In other words, there is no myelin being damaged or destroyed, so a magnetic resonance imaging (MRI) would not reveal a white spot (an MS lesion), as it likely would with MS exacerbation.

Besides biology, another distinguishing factor between an MS exacerbation and pseudo-exacerbation is time—an MS exacerbation lasts at least 24 hours and is separated from a prior exacerbation by at least 30 days. On the other hand, a pseudo-exacerbation usually lasts less than 24 hours. This is because once the outside trigger is removed, the symptoms resolve. (For example, you cool down after being in the hot sun.)

Pseudo-Exacerbation Triggers

There are multiple potential factors that may trigger an MS pseudo-exacerbation. By learning about these triggers, you can hopefully prevent pseudo-exacerbations in the future (as best as you can).


An infection, most commonly a urinary tract infection (UTI), is a frequent trigger of a pseudo-exacerbation.

Since many people with MS suffer from bladder problems, like decreased bladder sensation, they may not have the classic, obvious symptoms of a UTI (such as burning with urination or urinary urgency).

This is why in the event of a potential pseudo-exacerbation with an otherwise unknown trigger, many neurologists will order a urinalysis. In addition to a urinalysis, your healthcare provider may order a complete blood count to look for an increase in your white blood cells. In the end, treating the infection with an antibiotic will resolve the symptoms.

Increase in Core Body Temperature

Anything that increases your body temperature—taking a hot shower or bath, having a fever, engaging in strenuous exercise, or being outside in the heat—may result in a pseudo-exacerbation.

In fact, an increase of only .5 degrees Fahrenheit in core temperature is needed to trigger an increase in MS symptoms.

The good news is that once a person cools down, their MS symptoms resolve.

Due to the fact that this "heat trigger" is so common in people with MS (it even has its own name, called the Uhthoff phenomenon), MS healthcare providers frequently remind their patients to undertake cooling preventive strategies, such as:

  • Drinking cold water throughout the day, especially during hot summer months
  • wearing a brimmed hat, sunglasses, and light, breathable clothing in sunny weather
  • Dipping your feet and hands in cool water if feeling overheated
  • Wearing a cooling neck collar or vest or using a pocket fan when exercising or out in the sun

Lastly, if you have a fever, talk with your healthcare provider about taking a fever-reducing medication, such as Tylenol (acetaminophen). Of course, it's also important to treat the underlying illness.


While difficult to quantify, stress can trigger an increase in MS symptoms. Since stress may be related to depression and/or anxiety, your healthcare provider may suggest a combination of talk therapy with an anti-depressant or anti-anxiety medication.

Other stress-easing strategies include engaging in mind-body therapies like mindfulness meditation, relaxation training, and yoga. Keeping a journal, not over-scheduling, and daily exercise can also do wonders for your stress levels.


Fatigue is a very common symptom in MS, stemming from the disease itself, as well as other factors related to having MS. For instance, certain medications meant to ease MS symptoms, like vertigo, bladder problems, or spasticity may worsen your fatigue, which can then trigger a pseudo-exacerbation.

Likewise, fatigue in MS may stem from poor sleep habits, especially if you are getting up multiple times during the night to use the bathroom or to ease your leg cramps.

Combating MS fatigue often entails a multifaceted approach including aerobic exercise, adequate sleep, energy conservation, and sometimes, taking a stimulant medication, like Provigil (modafinil) or Symmetrel (amantadine). Mindfulness-based cognitive behavior therapy (MBCT) may also be helpful.

Hormone Changes

Hormone changes, such as those that occur during menstruation and menopause, may trigger a pseudo-exacerbation. If you find that your MS symptoms consistently flare during your monthly period, or are occurring as you approach menopause, it's sensible to speak with your healthcare provider about various treatment options.  

A Word From Verywell

MS is a complex neurological disease, and determining whether or not you may be suffering from a "pseudo" versus a "real" MS flare only adds to its mystery and unpredictable ways. Be sure to call your healthcare provider if you are not feeling well, sense something is off, and/or if you are experiencing new or worsening MS symptoms for more than a day. In some cases, what you may be thinking is a pseudo-exacerbation could be a real exacerbation—and while this is disheartening to learn, the faster you address it, the better.

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  • Birnbaum, M.D. George. 2013. Multiple Sclerosis: Clinician’s Guide to Diagnosis and Treatment, 2nd Edition. New York, New York. Oxford University Press.

  • Mirmosayyeb O et a. The interplay of multiple sclerosis and menstrual cycle: Which one affects the other one? Mult Scler Relat Disord. 2018 Apr;21:46-50. doi:10.1016/j.msard.2018.01.020

  • National MS Society. Managing Relapses. https://www.nationalmssociety.org/Treating-MS/Managing-Relapses

  • Tur C. Fatigue management in Multiple Sclerosis. Curr Treat Options Neurol. 2016;18:26. doi:10.1007/s11940-016-0411-8

By Colleen Doherty, MD
 Colleen Doherty, MD, is a board-certified internist living with multiple sclerosis.