Describe herpes zoster oticus.

Nature and Presentation

• The virus lies dormant in the sensory ganglion after chickenpox, and reactivates when cell-mediated immunity declines — with age, immunosuppression, HIV, malignancy, diabetes and stress. Ramsay Hunt in a young patient should prompt HIV testing
• The vesicles appear in the concha, external canal and postauricular skin — the small area of skin supplied by the sensory branch of the facial nerve, which is why this apparently obscure sensory territory matters

Management and Prognosis

• The prognosis IS significantly worse than bell’S palsy, and this is the central clinical fact: complete recovery occurs in only 50 to 60% against some 85 to 90% for Bell’s palsy, and a complete palsy at presentation carries a much worse outlook
• Treatment must begin early — ideally within 72 hours, and the benefit falls off sharply with delay.
• Antiviral — aciclovir 800 mg five times daily, or valaciclovir or famciclovir, for 7 to 10 days; intravenously in severe or immunosuppressed cases
• Corticosteroid — prednisolone 1 mg/kg tapering over 10 to 14 days.
• The combination of antiviral and steroid is standard in Ramsay Hunt, whereas steroid alone suffices in Bell’s palsy
• Analgesia, which is frequently the patient’s main concern, and may require gabapentin, pregabalin or amitriptyline for the neuropathic component
• Eye care IS the urgent priority and must not be left to the patient — lubricant drops by day, ointment and taping at night, a protective shield, and tarsorrhaphy if the cornea is threatened. The risk is greater than in Bell’s palsy.
• Vestibular sedatives for vertigo, used briefly only
• Physiotherapy and facial exercises once recovery begins; and surgical decompression, which is controversial and of unproven benefit
• Follow up with House-Brackmann grading and audiometry
• Complications — post-herpetic neuralgia.
• Prevention — the zoster vaccine reduces the incidence of shingles and of post-herpetic neuralgia in the elderly
• Otalgia precedes the rash, so the patient may present before there is anything visible in the canal
• Eighth nerve involvement distinguishes it from Bell palsy, giving deafness, tinnitus and vertigo alongside the facial weakness
• Recovery is only fifty to sixty per cent, against eighty-five to ninety for Bell palsy.
• Treat within seventy-two hours; the benefit of antiviral therapy falls off sharply after that