What is the workup for a patient with new onset paresthesias (abnormal sensations) to the face?

Workup for New Onset Facial Paresthesias

A thorough neurological evaluation with targeted diagnostic testing based on clinical suspicion is the recommended approach for new onset facial paresthesias, rather than routine laboratory or imaging studies. 1

Initial Clinical Assessment

History

• Onset characteristics: sudden vs. gradual progression
• Associated symptoms:
  • Dizziness, dysphagia, diplopia
  • Weakness or paralysis of facial muscles
  • Eye symptoms (dryness, inability to close)
  • Headache or altered mental status
  • History of malignancy or immunocompromise

Physical Examination

• Complete cranial nerve assessment (all 12 nerves)
• Facial muscle strength testing
• Sensory testing of face (light touch, temperature, pain)
• Eye examination for closure ability and corneal reflex

Diagnostic Testing

First-Line Laboratory Tests (when clinically indicated)

• Complete blood count
• Electrolytes and renal function
• Random glucose or HbA1c
• Vitamin B12 levels 1

Targeted Laboratory Testing (based on clinical suspicion)

• Lyme disease serology (in endemic areas)
• Autoimmune markers (ANA, RF, anti-CCP) if autoimmune etiology suspected
• Coagulation studies if vascular etiology suspected 1

Neuroimaging

Neuroimaging should not be performed routinely but reserved for specific indications:

• Focal neurological deficits
• Sudden onset with concern for TIA/stroke
• Progressive symptoms
• Associated headache
• Altered mental status
• History of malignancy or immunocompromise 1

Diagnostic Algorithm

1. If presenting with sudden-onset facial weakness/paresthesia:

   • Consider Bell's palsy (accounts for ~70% of facial nerve palsies) 1
   • Assess for complete eye closure
   • Start oral corticosteroids promptly if Bell's palsy suspected

2. If presenting with gradual onset or atypical features:

   • Consider structural causes (tumor, vascular lesion)
   • Obtain appropriate neuroimaging
   • Consider specialty consultation (neurology)

3. If presenting with systemic symptoms:

   • Obtain targeted laboratory testing based on suspected etiology
   • Consider infectious, inflammatory, or metabolic causes

Common Pitfalls and Caveats

• Don't miss central causes: Facial paresthesias can result from central nervous system abnormalities including ischemia, structural lesions, infection, inflammation, or degenerative conditions 2

• Avoid unnecessary testing: A systematic approach prioritizing targeted diagnostics based on clinical suspicion maximizes diagnostic yield while minimizing unnecessary testing 1

• Consider peripheral nerve entrapment: Peripheral causes include entrapment syndromes, metabolic disturbances, trauma, inflammation, connective tissue diseases, toxins, hereditary conditions, malignancies, and nutritional deficiencies 2

• Don't delay treatment for Bell's palsy: Early administration of corticosteroids significantly improves recovery rates in Bell's palsy 1

• Ensure eye protection: For patients with impaired eye closure, artificial tears during the day, lubricating ointment at night, and taping eyelids closed if necessary are crucial to prevent corneal damage 1