Investigation
Diagnosis made clinically in patients with
Typical presentation
- No risk factors or pre existing symptoms for other causes of facial paralysis
- Absence of cutaneous lesions of herpes zoster in external ear canal
- Normal neurological examination with the exception of the facial nerve
If atypical
- ESR, DM test, Lyme test, angiotensin – converting enzyme, chest imaging studies for possible sarcoidosis
- Lumbar puncture for Guillain – Barre syndrome
- MRI – swelling and uniform enhancement of geniculate ganglion and facial nerve
- CSF - Mild lymphocytosis