Herpes Zoster Ophthalmicus

Herpes zoster ophthalmicus (HZO) results from reactivation of varicella zoster virus (VZV) that has remained latent in the ophthalmic division (V1) of the trigeminal nerve since primary varicella infection.¹² HZO is considered an ophthalmic emergency because of its potential for severe ocular complications, chronic pain, and vision loss.¹ In the US, roughly one million herpes zoster cases occur annually, with HZO representing about 10% of them, and an overall herpes zoster incidence around 3.2 per 1000 person-years.³⁴

HZO commonly affects older adults and immunocompromised patients, and patients with HIV carry the highest relative risk; other risk factors include advancing age, immunosuppressive medication use, and primary varicella infection in infancy or in utero.¹⁴ In children, major risk factors are intrauterine varicella exposure or primary infection at a young age; HZO has also occurred in vaccinated children, and most affected children are actually immunocompetent.⁶ Ocular involvement occurs in approximately 50% of HZO cases.¹ Early corneal manifestations — dysesthesia and dendritiform keratopathy — are typically self-limited, but smoldering disease can produce ongoing pathological changes through direct viral invasion, secondary inflammation, and autoimmune mechanisms.²

HZO presents with a characteristic unilateral vesicular eruption in the V1 dermatome, and is typically a clinical diagnosis without extensive testing.¹⁶ Ocular symptoms include severe chronic pain and potential vision loss; acute keratitis is one of the most common ocular complications.¹⁵

Key differentials: herpes simplex virus keratitis, other causes of unilateral vesicular rash, primary varicella infection, other viral keratitis, contact dermatitis affecting the periorbital region, acute angle-closure glaucoma (for acute ocular pain), and other causes of dendritiform corneal lesions.

Exam reveals the unilateral vesicular eruption in the V1 distribution, corneal dysesthesia in early disease, dendritiform keratopathy as an early corneal manifestation, and signs of acute keratitis, sometimes including zoster stromal keratitis.^2,5 The characteristic dermatomal distribution typically allows clinical diagnosis without extensive testing.¹

Oral antiviral therapy is the mainstay of treatment and should be started promptly given the clinical (not lab-confirmed) diagnosis.⁵ Topical ganciclovir has a role for acute zoster keratitis unresponsive to oral antivirals, though this is a newer, less-established practice rather than a settled standard.⁵ Antivirals reliably resolve early signs and symptoms, but their effect on preventing later complications is less well established and needs further study.² Corticosteroids have a role in certain acute inflammatory complications, where the benefit of controlling inflammation is judged to outweigh the risk of locally reducing host immunity, and corneal complications sometimes require surgical intervention.² Management is often multidisciplinary, involving pain specialists, infectious disease, and sometimes psychiatry for chronic post-herpetic pain.⁴ The recombinant zoster vaccine (Shingrix) is now recommended by ACIP for healthy adults 50 years and older, replacing the older live vaccine (Zostavax) — vaccination is a genuinely primary-prevention intervention, not just a treatment adjunct.³⁴ In pediatric patients treated promptly with good adherence, vision recovery is generally good, though rare complications like optic neuritis can still cause irreversible vision loss.⁶

• HZO is an ophthalmic emergency requiring prompt recognition and treatment¹
• Ocular involvement occurs in approximately 50% of HZO cases, making careful ophthalmologic evaluation essential in every patient¹
• Both healthy and immunocompromised children can develop HZO, with most affected children being immunocompetent⁶
• Prevention through Shingrix vaccination is now recommended over the older live vaccine³
• Common pitfall: delaying antiviral treatment while awaiting confirmatory testing, when the diagnosis is primarily clinical¹
• Common pitfall: failing to recognize that HZO can occur in immunocompetent individuals, not just those who are immunocompromised⁶
• Common pitfall: assuming early self-limited findings will not progress to vision-threatening complications without appropriate treatment²