Bell palsy

Background

• Idiopathic unilateral facial nerve palsy (not sparing forehead)
• Suspected etiologies include HSV-1 or other viral infection

Differential Diagnosis

• Idiopathic, possibly related to viral inflammation of the facial nerve
• Infections
  • Ramsay Hunt syndrome (VZV)
  • HSV
  • Other viral infections, including coxsackievirus, COVID, CMV, EBV, influenza A and B, mumps, rubella
  • Lyme disease (may be bilateral, with or without meningitis)
  • Rarely, Ehrlichia, Rickettsia, tertiary syphilis
  • HIV, with or without opportunistic infection
  • Complication of otitis media or mastoiditis
• Autoimmune/inflammatory
  • Guillain-Barré syndrome
  • Sarcoidosis
  • Sjögren syndrome
• Structural
  • Tumours, including cholesteatoma, cutaneous squamous cell carcinoma, glomus tumour, meningioma, parotid tumour, schwannoma
  • Stroke, typically sparing the forehead and eyelid muscles
• Iatrogenic, from botox injection

Management

• Corticosteroids (NNT 50 for mild-to-moderate, 8 for severe)
• No role for antivirals alone, but can consider adding in cases of severe Bell palsy

Further Reading

• de Almeida JR, et al. Management of Bell palsy: clinical practice guideline. CMAJ. 2014;186(12)917-922.