What are the signs and symptoms of a multiple sclerosis (MS) flare?

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Last updated: August 26, 2025View editorial policy

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Signs and Symptoms of Multiple Sclerosis Flare

Multiple sclerosis flares typically present with new or worsening neurological symptoms that develop over days to weeks, including visual disturbances, sensory changes, motor weakness, and cognitive difficulties depending on which areas of the central nervous system are affected.

Common Presentations of MS Flares

Visual Symptoms

  • Optic neuritis (occurs in 20-31% of initial presentations) 1
    • Visual impairment or loss
    • Scotoma (blind spots)
    • Red-green color desaturation
    • Pain with eye movement
    • Blurred vision 2

Sensory Symptoms

  • Paresthesia (tingling, pins and needles sensation) 2
  • Numbness in limbs 1
  • Electric-shock sensations (particularly with neck flexion, known as Lhermitte's sign) 1
  • Sensory disturbances 3

Motor Symptoms

  • Weakness in limbs 1
  • Paraparesis (partial paralysis of lower limbs) 2
  • Hemiparesis (weakness affecting one side of the body) 2
  • Monoparesis (weakness in one limb) 2
  • Tremor or lack of coordination 1
  • Gait problems
  • Spasticity

Brainstem and Cerebellar Symptoms

  • Diplopia (double vision) 2
  • Internuclear ophthalmoplegia (failure of ipsilateral eye adduction with contralateral eye abduction nystagmus) 4
  • Vertigo
  • Ataxia (lack of coordination)
  • Dysarthria (speech difficulties) 2

Cognitive and Psychological Symptoms

  • Difficulty concentrating
  • Memory problems
  • Fogginess
  • Behavioral and neuropsychological alterations 2
  • Emotional changes (irritability, sadness, nervousness)

Other Common Symptoms

  • Fatigue (often severe and debilitating) 1
  • Bladder and bowel dysfunction 1
  • Sexual dysfunction
  • Heat sensitivity (symptoms worsen with increased body temperature)
  • Aphasia (language difficulties) 2

Characteristics of MS Flares

Temporal Pattern

  • Symptoms typically develop over days to weeks
  • Last at least 24 hours 5
  • May persist for weeks to months
  • Often improve with time or treatment

Spatial Pattern

  • Symptoms reflect the location of lesions in the central nervous system
  • May affect multiple neurological systems simultaneously
  • Commonly involve optic nerves, spinal cord, brainstem, and cerebellum 4

Diagnostic Features on Imaging

MRI Findings During Flares

  • New or enlarging T2-hyperintense lesions 1
  • Gadolinium-enhancing lesions indicating active inflammation 1
  • Characteristic locations:
    • Periventricular (around ventricles)
    • Juxtacortical (touching or within the cortex)
    • Infratentorial (brainstem, cerebellar)
    • Spinal cord 2

Red Flags (Atypical for MS)

Symptoms that should prompt consideration of alternative diagnoses:

  • Sudden onset of bilateral hearing loss
  • Antecedent fluctuating hearing loss
  • Severe bilateral vestibular loss
  • Concurrent eye pain, redness, lacrimation, and photophobia
  • Recent head trauma or barotrauma
  • Intractable nausea, vomiting, or hiccups (may suggest area postrema syndrome in NMOSD) 2

Clinical Pearls

  • MS symptoms vary widely depending on which nerve fibers are affected 1
  • Symptoms often worsen with heat exposure or fever (Uhthoff's phenomenon)
  • Relapse severity can range from mild to severely disabling
  • Symptoms may completely resolve between flares in relapsing-remitting MS
  • Persistent symptoms may indicate progression rather than acute flare
  • Early recognition and treatment of flares can help prevent long-term disability

Understanding these signs and symptoms is crucial for early diagnosis and treatment of MS flares, which can help prevent long-term disability and improve quality of life for patients with multiple sclerosis.

References

Guideline

Multiple Sclerosis Diagnosis and Management

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Disorders of vision in multiple sclerosis.

Clinical & experimental optometry, 2022

Research

Clinical presentation and diagnosis of multiple sclerosis.

Clinical medicine (London, England), 2020

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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