Description

• Eye infection (blepharitis, conjunctivitis, keratitis, stromal keratitis, uveitis, retinitis, glaucoma, or optic neuritis) caused by herpes simplex virus (HSV) types 1 and 2 or varicella-zoster virus (VZV, or human herpes virus type 3)
• Categories: Neonatal, primary, and recurrent:
  • Herpes virus most commonly affects the cornea; HSV type 1 is most often implicated in herpes keratitis.
  • Called shingles or herpes zoster ophthalmicus (HZO) when there is involvement of the ophthalmic division of the 5th cranial nerve due to VZV reactivation
  • Both HSV and HZO classically cause a dendritic keratitis best seen with fluorescein staining by slit-lamp examination.
  • Reactivation of latent infection is most common for both.
  • Primary HSV keratitis is more common in children.
• System(s) affected: Eye; Skin; Central Nervous System (CNS) (neonatal)

Epidemiology

• Predominant age: HSV, mean age of onset 37.4, can occur at any age; HZO, usually advancing age (>50)
• Predominant sex: HSV, Male = Female; HZO, Female > Male

• HSV ocular infection: 11.8/100,000 annually in the US (1)
• Zoster: 2.2–3.4/1,000 people annually; lifetime risk is 20–30%:
  • HZO represents 10–20% of all cases of HZ

• HSV ocular infection prevalence is ~150/100,000 population.

• HZO: 20–30% of the general population will develop HZ sometime in their lives with about a 1% chance of developing HZO.

Risk Factors

• HSV: History or close contact with HSV-infected person:
  • General risk factors for reactivation: Stress, trauma, fever, UV light exposure, other viral infections
  • Risk factors for HSV keratitis: UV laser eye treatment, some topical ocular medications such as prostaglandin analogues, and primary/secondary immunosuppression
• HZO: History of varicella infection:
  • Advancing age (>50), sex (female > male), trauma, stress, immunosuppression

ALERT
Consider primary/secondary immunodeficiency disorders in all zoster patients <40 (e.g., AIDS, malignancy).

General Prevention

• Contact precautions with active lesions
• VZV can be spread to those who have not had chickenpox and are not immunized.
• Antiviral prophylaxis necessary if started on topical steroids
• Varicella vaccination (Zostavax): Single 0.65 mL SC dose; no booster. There is no need to inquire about history of varicella or to perform testing for antibody. Can be given to those with prior zoster episode. Not used in treatment of acute zoster or postherpetic neuralgia (PHN).
• Acyclovir can be used prophylactically to prevent recurrence.

ALERT
Zoster vaccination is contraindicated if HIV-positive, other immunocompromised state, or in active untreated tuberculosis (TB).

• Pregnant women without history of chickenpox should avoid contact with persons with active zoster.
• Pregnancy increases risk of recurrence.
• Live vaccine is contraindicated during pregnancy.

Pathophysiology

• HSV and VZV are DNA viruses of the Herpesviridae family.
• Primary infection from contact with infected person leads to a latent state within trigeminal ganglia (HZO).
• Reactivation of the virus affecting the ophthalmic branch is common and can lead to direct ocular involvement.

Etiology

• Primary infections:
  • Neonatal is usually HSV-2
  • Primary ocular HSV is usually HSV-1.
• Recurrent infections:
  • Reactivation from trigeminal ganglion
  • HSV-1, HSV-2, or VZV

Commonly Associated Conditions

Primary and secondary immunocompromised states