What is the recommended treatment for herpetic keratitis?

Treatment of Herpetic Keratitis

For herpetic keratitis, the recommended treatment is a combination of topical antiviral agents (ganciclovir 0.15% gel three to five times daily or trifluridine 1% solution five to eight times daily) along with oral antiviral therapy (acyclovir 200-400 mg five times daily, valacyclovir 500 mg two to three times daily, or famciclovir 250 mg twice daily). 1

First-Line Treatment Options

Topical Antiviral Medications

• Ganciclovir 0.15% gel: Apply 3-5 times daily - preferred due to better ocular surface tolerability and less toxicity with prolonged use 1, 2
• Trifluridine 1% solution: Apply 5-8 times daily - effective but causes epithelial toxicity if used longer than 2 weeks 1

Oral Antiviral Medications

• Acyclovir: 200-400 mg five times daily 1
• Valacyclovir: 500 mg two to three times daily 1
• Famciclovir: 250 mg twice daily 1

Treatment Algorithm Based on Type of Herpetic Keratitis

Epithelial Herpetic Keratitis

• Start with topical antiviral (preferably ganciclovir 0.15% gel) 3-5 times daily 1, 3
• Consider adding oral antiviral therapy in moderate to severe cases 1
• Avoid topical corticosteroids as they potentiate HSV epithelial infections 1
• Follow up within 1 week to assess response with visual acuity measurement and slit-lamp biomicroscopy 1

HSV Stromal Keratitis

• Combination of oral antiviral therapy and topical corticosteroids at minimum effective dose 1
• Oral antivirals are essential when using topical steroids to prevent viral replication 1
• Taper corticosteroids slowly once inflammation is controlled 1
• Use corticosteroids with poor ocular penetration (fluorometholone, loteprednol) to minimize IOP elevation and cataract formation 1

Special Considerations

Recurrent HSV Keratitis

• Consider long-term prophylaxis with lower doses of oral antivirals 1
• Topical ganciclovir has shown effectiveness in preventing recurrences, particularly in patients with penetrating keratoplasty 2
• Identify and minimize triggers such as stress, illness, and trauma 4

Treatment-Resistant Cases

• Higher doses of oral antivirals may be effective in cases demonstrating resistance to therapy 1
• For immunocompromised patients with resistant strains, consider adding interferon alpha-2a as an adjunctive therapy 5
• Reculture if there is no clinical improvement within 48 hours 1

Monitoring and Follow-up

• Schedule follow-up within 1 week of initiating treatment 1
• Assess for:
  • Reduced pain and discharge 1
  • Decreased corneal infiltrate density 1
  • Initial re-epithelialization 1
  • Cessation of progressive corneal thinning 1
• Regular monitoring of IOP and pupillary dilation if using topical corticosteroids 1

Potential Complications and Management

• Corneal scarring: May require keratoplasty in severe cases 4
• Persistent epithelial defects: Consider adjunctive therapies (lubrication, bandage contact lens, amniotic membrane) 1
• Secondary bacterial infection: Treat with appropriate antibiotics based on culture results 1
• Neurotrophic keratopathy: May develop due to corneal nerve damage from recurrent HSV infections 1

Pitfalls to Avoid

• Using topical corticosteroids without antiviral coverage in epithelial HSV keratitis - this can potentiate the infection 1
• Tapering topical antibiotics below therapeutic dosing, which may increase risk of resistance 1
• Prolonged use of trifluridine beyond 2 weeks due to epithelial toxicity 1
• Failure to distinguish between medication toxicity and worsening infection 1

By following this treatment approach, most cases of herpetic keratitis can be effectively managed to minimize corneal damage, preserve vision, and reduce the risk of recurrence.