Kristin M. Hammersmith
• Acute, painful, vesicular eruption distributed along the ophthalmic branch of the trigeminal nerve (1).
• Ocular inflammation without characteristic rash: Zoster sine herpete (2).
• 200,000 new cases per year in the US.
• 1% life time risk (3).
• Increasing age.
• Immune compromise (i.e., HIV, cancer, immunosuppression) (4).
• CDC recommendation (2008)—routine vaccination of all individuals 60 years or older with Varicella Zoster Vaccination (Zostavax®), including those with prior history of herpes zoster or chronic medical conditions.
• The vaccine is not licensed for the treatment of acute HZ or post herpetic neuralgia (PHN), or for the prevention of HZ in patients aged younger than 60 years (5).
• Reactivation of latent virus from trigeminal ganglia with viremia and spread of virus from sensory axons to skin.
• Age-related decline in varicella-zoster virus specific cell mediated immunity increases susceptibility to viremia (5).
• Painful vesicular eruption in a single dermatome.
• Fever, malaise, headache, and pain in the affected dermatome.
• Affective disorder: Anorexia, lassitude, mood changes, antisocial behavior, depression, and insomnia (6).
• Rash involving the V1 dermatome evolving from an erythematous lesion with macules, papules and vesicles with pustules and crusts developing subsequently.
• Slit-lamp examination.
– Eyelid: Hyperemia, edema, ptosis.
– Conjunctiva: Hyperemia, petechial hemorrhages, vesicles, pseudodendrites, papillae, follicles, pseudomembranes.
– Sclera/episclera: Limbal vasculitis, sclerokeratitis, posterior scleritis.
– Epithelium: Pseudodendrites, punctate epithelial keratitis.
– Stroma: Nummular stromal keratitis, disciform keratitis (7).
– Retina/optic nerve: Retinal perivasculitis, ischemic optic neuritis, necrotizing retinopathy.
– Late (1 month after rash):
Eyelid: Cicatricial entropion/ectropion, trichiasis.
Conjunctiva: Hyperemia, pseudomembranes.
Sclera/episclera: Limbal vasculitis, sclerokeratitis, posterior scleritis.
Epithelium: Delayed pseudodendrites (mucous plaque keratitis), punctate epithelial keratitis, neurotrophic ulceration, band keratopathy (10).
Stroma: Nummular stromal keratitis, disciform keratitis, lipid deposition, anterior and posterior stromal scarring, chronic edema (7).
Iris/Uvea: Segmental iris atrophy, granulomatous keratouveitis with KP, secondary glaucoma.
Retina: Acute retinal necrosis (ARN), progressive outer retinal necrosis (PORN).
• Neuroophthalmic examination.
– Extraocular muscles: Transient EOM palsy and diplopia (11).
– Cranial nerves: CN III, IV, or VI can be involved indicating vasculitis within the orbital apex (orbital apex syndrome) or brainstem dysfunction (12).
– Acute pain: Characterized as lancinating, burning, aching, and/or itching.
– Post-herpetic neuralgia (PHN)—pain lasting more than 1 month after disease onset. Characterized as constant or intermittent aching or burning, sudden lancinating pain, allodynia (pain from nonpainful stimuli), and/or a constant or intermittent itch (13).
DIAGNOSTIC TESTS & INTERPRETATION
No laboratory work up is necessary unless there is a high index of suspicion for HIV.
Slit-lamp examination including intraocular pressure assessment, corneal sensation, and dilated funduscopic examination.
Follow-up & special considerations
• Starting oral antiviral therapy shortens the duration of acute pain, virus shedding, rash, acute, and late-onset anterior segment complications, and the incidence and severity of PHN (12).
• Depending on severity of ocular inflammation, patient should be re-evaluated within 5–7 days and frequency of follow-up visits should be dictated by severity of slit-lamp findings.
Treatment with valacyclovir in severe immunocompromise has been associated with thrombocytopenic purpura/hemolytic uremic syndrome and is therefore not FDA approved for use in this subset of patients.