How do you assess for eye involvement in a patient with herpes zoster on the forehead?

Assessment of Eye Involvement in Herpes Zoster on the Forehead

A thorough ophthalmic examination is essential for all patients with herpes zoster on the forehead as approximately 50% of patients with herpes zoster ophthalmicus (HZO) develop ocular disease, with up to 25% developing chronic or recurrent complications. 1

Initial Assessment

Key Clinical Signs to Evaluate

• Hutchinson's sign: Presence of vesicles on the tip of the nose (highly predictive of ocular involvement) 2
• Eyelid involvement: Check for blepharitis, vesicular lesions, and cicatricial changes 3, 4
• Corneal sensation: Test using a cotton wisp (absent sensation indicates significant risk) 2

Comprehensive Eye Examination

1. Visual acuity measurement: Baseline assessment critical for monitoring disease progression 3
2. Slit-lamp biomicroscopy: Essential for detecting:
   • Conjunctival involvement (conjunctivitis, vesicles, hyperemia)
   • Corneal lesions (epithelial defects, pseudodendrites, stromal keratitis)
   • Anterior chamber inflammation (cells, flare, hypopyon)
   • Iris involvement (sectoral atrophy)
   • Intraocular pressure measurement (secondary glaucoma risk) 3
3. Pupillary examination: Check for paralytic mydriasis 4

Specific Ocular Manifestations to Assess

Anterior Segment

• Conjunctivitis: One of the most common manifestations (69% of cases) 5
• Keratitis: Various forms including epithelial, stromal, and neurotrophic (60% of cases) 5
• Episcleritis/Scleritis: Less common but potentially serious (12% of cases) 5
• Anterior uveitis: Significant predictor of visual loss (31% of cases) 2, 5

Intraocular Pressure

• Ocular hypertension: Present in approximately 43% of cases, associated with almost every ocular manifestation 5

Posterior Segment

• Optic nerve involvement: Examine for optic neuritis or perineuritis 4
• Fundus examination: Though retinal involvement is uncommon, a complete exam is necessary 1, 5

Follow-up Assessment

Timing

• Initial follow-up: Within 1 week if ocular involvement is detected 3
• Subsequent visits: Regular monitoring based on severity of involvement
• Long-term follow-up: At 3 and 6 months to assess for late sequelae 2

Monitoring Parameters

• Visual acuity: To track improvement or deterioration
• Intraocular pressure: Especially if on corticosteroid treatment
• Slit-lamp examination: To monitor resolution or progression of inflammation
• Corneal sensation: To assess for neurotrophic keratitis 3

Risk Factors for Poor Visual Outcome

• Advanced age: Stronger association with visual loss 2, 5
• Positive Hutchinson's sign: Strong predictor of ocular involvement 2
• Absent corneal sensation: Associated with neurotrophic keratitis 2
• Presence of uveitis: Best predictor of visual loss on multivariate analysis 2
• Immunocompromised status: Higher risk of severe manifestations 1, 5

Common Pitfalls to Avoid

1. Delayed assessment: Early recognition and treatment are critical to prevent complications
2. Missing Hutchinson's sign: This is a key predictor of ocular involvement
3. Inadequate IOP monitoring: Especially in patients on topical corticosteroids
4. Overlooking late complications: Some ocular manifestations can occur weeks after the initial rash 4
5. Inappropriate corticosteroid use: Topical steroids should be used cautiously and with concurrent antiviral therapy 3, 6

Remember that urgent ophthalmologic consultation is warranted for any patient with herpes zoster on the forehead, as early intervention can significantly reduce the risk of vision-threatening complications.