Herpes Zoster Ophthalmicus

29/01/2025

Author: Dr Naomi Melamed 

Introduction
Herpes Zoster Ophthalmicus (HZO) is a reactivation of the varicella-zoster virus (VZV) affecting the ophthalmic branch of the trigeminal nerve. It can lead to significant ocular complications if not promptly diagnosed and treated.

Diagnosis

HZO is suspected in patients presenting with a painful rash localized to the forehead, eyelid, or the nose (Hutchinson's sign), often associated with ocular symptoms. The diagnosis is largely clinical, based on the characteristic rash and patient history, particularly a prior history of chickenpox or shingles. Laboratory tests such as PCR (Polymerase Chain Reaction) of fluid from the lesion or eye can confirm the presence of VZV.

Examination Findings

  • Rash: A unilateral vesicular rash with erythema typically develops along the ophthalmic distribution of the trigeminal nerve, often sparing the midline.

  • Eye Involvement: Conjunctivitis, corneal involvement (dendritic ulcers), and uveitis are common ocular findings. Ocular motility may be affected, and visual acuity can decrease.

  • Hutchinson's sign: Lesions on the tip or side of the nose are a key indicator of possible ocular involvement.

  • Pain: Severe, burning, or stabbing pain often precedes the rash, which is a hallmark feature.

Investigations

  • PCR Testing: From ocular fluid or vesicular fluid to confirm the diagnosis.

  • Slit Lamp Examination: To check for corneal ulcers, anterior uveitis, or other ocular complications.

  • Viral Culture: Less commonly used, as PCR is more sensitive.

  • Serology: Can show prior exposure to VZV but is not diagnostic for acute infection.

Treatment

Early antiviral therapy is crucial in preventing complications. Acyclovir, Valacyclovir, and Famciclovir are commonly used antivirals, with the treatment typically starting within 72 hours of rash onset for optimal outcomes. Topical antiviral therapy may be used for ocular lesions, and corticosteroids are sometimes prescribed for inflammation in severe cases. For pain relief, NSAIDs or tricyclic antidepressants (e.g., amitriptyline) may be utilized, especially in postherpetic neuralgia.

Complications

  • Postherpetic Neuralgia (PHN): Chronic pain lasting months to years after the rash has resolved is one of the most common complications.

  • Vision Loss: Corneal scarring, uveitis, or secondary glaucoma can cause irreversible damage to the eye and result in vision loss.

  • Keratitis and Dendritic Ulcers: Can lead to permanent corneal scarring if untreated.

  • Acute Retinal Necrosis (ARN): A rare but serious complication that can cause rapid vision loss.

Conclusion

Herpes Zoster Ophthalmicus requires timely diagnosis and treatment to prevent serious ocular complications and long-term pain. With early intervention using antivirals and appropriate pain management, outcomes can be significantly improved.

References

  1. M. M. Spruance et al., "Varicella-zoster virus infections," Lancet, vol. 380, no. 9857, pp. 711-723, 2012.

  2. M. W. Levin, "Herpes Zoster Ophthalmicus," JAMA Ophthalmology, vol. 132, no. 9, pp. 1062-1063, 2014.

  3. T. M. Gilden et al., "The epidemiology of herpes zoster," J Infect Dis, vol. 199, no. 7, pp. 1058-1065, 2009.

  4. J. E. Brown et al., "Management of herpes zoster ophthalmicus," Ophthalmology, vol. 121, no. 6, pp. 1219-1227, 2014.


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