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Herpes Zoster Ophthalmicus

URGENT — Cornea

Symptoms

prodrome: dermatomal pain, paresthesias, headache, fever, and malaise

acute: painful vesicular skin rash, blurred vision, and red eye

chronic: postherpetic neuralgia (persistent pain after rash resolution)

Clinical Findings

Cutaneous signs

  • acute vesicular rash respecting the midline in the v1 (trigeminal) distribution
  • unilateral involvement; typically spares the lower eyelid (v2)
  • hutchinson sign: vesicles on the tip or side of the nose (nasociliary branch involvement)

Ocular signs

  • pseudodendritic keratitis: elevated mucous plaques without terminal bulbs
  • stromal keratitis, endotheliitis, and neurotrophic keratopathy
  • anterior uveitis (often with sector iris atrophy) and secondary glaucoma
  • episcleritis or scleritis

Severe/neurological

  • retinitis: acute retinal necrosis (arn) or progressive outer retinal necrosis (porn)
  • optic neuritis and cranial nerve palsies (iii, iv, vi)
  • vzv vasculitis (stroke risk weeks after hzo)

Etiology

Pathogenesis

  • reactivation of varicella-zoster virus (vzv) from the trigeminal (v1) ganglion

Risk factors

  • age >50 years
  • immunocompromise: hiv, malignancy, chemotherapy, or organ transplant

Mechanism

  • direct viral invasion (epithelium/retina) and immune-mediated inflammation (stroma/uvea)

Red Flags

hutchinson sign: high risk for ocular involvement; mandates slit-lamp exam

acute retinal necrosis: peripheral necrotizing retinitis with vitritis

corneal perforation or severe necrotizing stromal thinning

contralateral hemiparesis weeks post-hzo: suggests vzv-related stroke

Investigations

Ocular diagnostics

  • slit-lamp exam with iop measurement and corneal staining (fluorescein/rose bengal)
  • dilated fundus exam: mandatory to rule out peripheral retinitis (arn/porn)

Systemic screening

  • consider hiv testing or malignancy screen in young/healthy patients with hzo
  • neuroimaging (mra/mri) if neurological deficits or vzv vasculitis suspected

Treatment

Systemic antivirals (7–10 days)

  • valacyclovir 1 g t.i.d. (preferred)
  • famciclovir 500 mg t.i.d.
  • acyclovir 800 mg 5x/day
  • iv acyclovir 10 mg/kg q8h for retinitis, cns, or immunocompromised patients

Ocular therapy

  • uveitis/stromal keratitis: topical prednisolone acetate 1% (4–8x/day) + cycloplegic
  • epithelial plaques: topical ganciclovir gel or lubricants
  • secondary glaucoma: aqueous suppressants (avoid prostaglandins)

Supportive & chronic

  • skin: bacitracin or erythromycin ointment to lesions to prevent superinfection
  • neurotrophic: aggressive lubrication, serum tears, or tarsorrhaphy
  • pain: gabapentin, pregabalin, or tcas for neuralgia

Clinical Pearl

Hutchinson sign (rash on tip of nose) predicts ocular involvement because the nasociliary nerve supplies both the nose tip and the eye. Start antivirals within 72 hours to reduce post-herpetic neuralgia and eye complications.

Differential Diagnosis

  • herpes simplex virus (hsv) keratitis (true dendrites with terminal bulbs)
  • acanthamoeba keratitis
  • adenoviral keratoconjunctivitis
  • varicella (primary chickenpox)

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