Herpes zoster ophthalmicus

Case

• A 42-year-old man presents with a viral illness. He also complains of tingling on the left side of his forehead and blurring of his vision. On examination, he has a red left eye and a vesicular rash to the tip of his nose. You suspect herpes zoster opthalmicus and make a referral to ophthalmology. 

• Patients with ocular symptoms should immediately be referred to an ophthalmologist for further management. Patients should also be started on systemic antiviral treatment (e.g. oral aciclovir) within 72 hours of the onset of the rash. 

• Antibiotics should not be used unless secondary bacterial infection is suspected. Sodium cromoglicate is used for irritating eye symptoms from hay fever and timolol is used in primary open angle glaucoma. There is no role for topical daktacort in herpetic eye disease.

Herpes simplex - ocular

• Ocular HSV infections (usually HSV-1; rarely HSV-2) can cause inflammation of the retina (retinitis), iris and associated uveal tract (iritis or uveitis), cornea (keratitis), conjunctiva (conjunctivitis), eyelids (blepharitis), and surrounding skin (periocular dermatitis).

• The majority of primary HSV ocular infection is asymptomatic. If symptomatic, it usually presents with blepharoconjunctivitis.

• Recurrent HSV ocular infection is more common clinically, and lesions typically cause keratitis which may affect one or more of the three corneal layers:

  • Epithelial — the most common ocular manifestation of HSV infection, accounting for 50–80% of cases.

  • Stromal — which may be non-necrotizing or necrotizing.

  • Metaherpetic ulcer (trophic keratitis).

• HSV-1 is usually transmitted through direct contact with active orofacial lesions or infected secretions such as saliva or tears, from a person who is actively shedding the virus.

  • HSV persists in a latent state in the trigeminal nerve ganglion, where it can remain latent indefinitely or can reactivate, leading to viral shedding at the corneal surface.

Complications include:

• • Corneal scarring and visual impairment.

  • Corneal perforation.

  • Secondary infection with bacteria or fungi.

  • Systemic infection, such as aseptic meningitis, encephalitis, or hepatitis.

Prognosis is variable:

• • Blepharoconjunctivitis tends to resolve within 2 weeks, and epithelial keratitis tends to resolve in 1–2 weeks.

  • About 25% of people with epithelial keratitis will develop stromal keratitis or iritis.

  • Recurrent ocular HSV is common, with the risk increasing after each subsequent episode.

Diagnosis in primary care is clinical. Symptoms and signs include:

• • Eye pain, eye irritation or watering, and photophobia.

  • Blurred vision.

  • An acute red eye.

  • Crops of vesicles, ulcers, or pustules along the lid margin or periocular skin.

  • A hazy cornea or creamy opacity (suggests stromal keratitis).

  • A fixed irregular pupil or limbal injection (suggests iritis or uveitis).

  • Reduced corneal sensation.

  • Reduced visual acuity.

Assessment of a person with suspected ocular herpes simplex infection includes asking about previous episodes and trigger factors for recurrent episodes, associated complications, and conditions that may affect prognosis, such as immunosuppression or atopy.

• • A general examination to check for systemic infection, such as pyrexia, lymphadenopathy, and hepatosplenomegaly.

  • Fluorescein staining of the cornea to check for a dendritic or amoeboid ulcer, suggesting epithelial involvement.

  • Checking visual acuity.

Management of a person with suspected ocular HSV includes:

• • Referral of all cases to eye casualty or an emergency eye service for same-day assessment and specialist management.

  • If same-day assessment is not possible or practical, specialist ophthalmological advice should be sought regarding initiating drug treatment in primary care.

  • Note: some optometrists can initiate topical antiviral treatment for suspected epithelial keratitis in specific clinical circumstances.

Resources

• Herpes simplex - ocular (CKS)