Ramsay-Hunt Syndrome

Ramsay Hunt syndrome is caused by reactivation of latent varicella-zoster virus in the geniculate ganglion of the facial nerve (CN VII). It is a reactivation event after prior varicella exposure, not a new primary varicella infection. The reactivated virus produces inflammation and oedema around CN VII as the nerve travels through the narrow bony facial canal. The swollen nerve has little room to expand, so conduction becomes impaired and ipsilateral facial weakness develops. Vesicles arise in the sensory distribution of the affected nerve, commonly the external auditory canal, concha, tongue, or soft palate. The classic triad is: - severe ipsilateral ear pain; - vesicular lesions in or around the ear or on the oral mucosa; and - ipsilateral peripheral facial palsy. A peripheral facial palsy weakens the entire ipsilateral face, including the forehead. The patient may be unable to wrinkle the forehead, close the eye, smile symmetrically, or fully inflate the cheek. This contrasts with the usual central facial weakness of a stroke, in which the forehead is relatively spared because it receives bilateral cortical innervation. The rash may be...