Herpes Zoster Ophthalmicus

• Herpes zoster ophthalmicus (HZO) refers to shingles affecting the ophthalmic branch (V1) of the trigeminal nerve.
• HZO can involve any part of the eye or orbit, ranging from potentially benign, to sight- or life-threatening complications.
• Primary infection with VZV manifests as chickenpox (varicella). Following resolution, viruses establish latent infection within sensory nerve ganglions. Reactivation of such dormant viruses results in shingles (herpes zoster). Involvement of the ophthalmic branch of the trigeminal nerve (V1) results in herpes zoster ophthalmicus (HZO).
• Chickenpox = Varicella zoster virus

  Shingles = herpes zoster
• Risk factors:

  • Advancing age (>60)
  • Immunosuppressed
  • Pregnancy
  • Neonates
• Ocular involvement occurs in approximately 50% of patients with HZO. There is no correlation between the severity of skin rash and the extent of ocular complications.
• Typical symptoms of HZO include:

  • Viral prodromal phase: fever, malaise, headache
  • Pre-herpetic neuralgia: paraesthesia and pain along the affected dermatome of V1. If this pain persists for longer than one month after the rash has healed, it is termed post-herpetic neuralgia.
  • Rash: a characteristic, unilateral rash following the dermatomal distribution of V1
  • Zoster sine herpete: neuropathic pain not accompanied by a characteristic rash
• HZO may involve any part of the globe or none. Symptoms may vary depending on the structures affected, and this can guide clinical examination:

  • Isolated conjunctivitis and corneal involvement present with mildly reduced visual acuity, red eye, sharp pain, foreign body sensation and epiphora (excessive tearing)
  • The presence of photophobia, dull eye pain and new floaters may indicate uveitis warranting urgent ophthalmological opinion. This may be 1-3 weeks following the onset of the rash.
  • Symptoms of diplopia may indicate associated extraocular muscle palsy. 
• Clinical exam:

  • Eyelid erythema and oedema
  • Crusted lesions in the upper lid and along the rest of the V1 dermatomal distribution
  • Conjunctiva injection
  • Cornea - fluorescein staining reveals keratitis
  • Signs of anterior uveitis
  • Cranial nerve palsy
  • Reduced corneal sensation
• Hutchinson’s sign refers to cutaneous lesions on the tip, side or root of the nose which indicates involvement of the V1 nasal branch. This is a strong predictor of ocular involvement.
• The diagnosis of HZO is clinical in the vast majority of cases with the identification of characteristic skin lesions.

  Relevant investigations may include:

  • Conjunctival or skin swabs of lesions can be sent for confirmatory viral PCR
  • Suspected cerebral involvement (rare) will require neuroimaging and/or lumbar puncture
• Management:

  • Antiviral therapy (Aciclovir)- ideally within 72 hours
  • Pain management - paracetamol + NSAID or amitriptyline
  • Consider oral corticosteroids in the first 2 weeks in immunocompromised adults, only in combination with antivirals
  • Supportive - cold compress, pain killers, topical lubricants
• Complications:

  • Postherpetic neuralgia - most common complication
  • Repeat corneal ulcers - results in corneal thinning and perforation
  • Vision-threatening involvement of the posterior segment of the eye e.g. optic neuritis
  • 3rd, 4th and 6th cranial nerve palsies
  • Systemic complications - encephalitis, GBS, pneumonitis, stroke and vasculitis