Herpes zoster is a viral infection that usually presents as a childhood infection of varicella (ie, chicken pox). The pathogen is human herpesvirus-3 (HHV-3), also known as the varicella zoster virus. Following the acute phase, the virus enters the sensory nervous system, where it is harbored in the geniculate, trigeminal, or dorsal root ganglia and remains dormant. Even after the acute rash subsides, pain can persist or recur in shingles-affected areas. This condition is known as postherpetic neuralgia (PHN).
Postherpetic neuralgia, or pain persisting after the rash has resolved (often defined specifically as pain persisting for 90 days or more after the onset of the rash), is a feared complication of herpes zoster.
Approximately 1 million new cases of herpes zoster (HZ) occur in the United States annually, including 10%-20% with herpes zoster ophthalmicus (HZO). Postherpetic neuralgia, a debilitating pain syndrome occurs in 30% HZ, whereas 50% HZO develop ophthalmic complications. Diplopia from cranial nerve palsy occurs in less than 30% HZO, whereas optic neuropathy is seen in less than 1% HZO.
Herpes zoster ophthalmicus (HZO) is a clinical manifestation of the reactivation of latent varicella zoster virus (VZV) infection and is more common in people with diminished cell-mediated immunity. Lesions and pain correspond to the affected dermatomes, mostly in first or second trigeminal branch and progress from maculae, papules to vesicles and form pustules, and crusts. Complications are cutaneous, visceral, neurological, ocular, but the most debilitating is post-herpetic neuralgia. Herpes zoster ophthalmicus may affect all the ophthalmic structures, but most severe eye-threatening complications are panuveitis, acute retinal necrosis (ARN) and progressive outer retinal necrosis (PORN) as well.
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