A 28-year-old man from Mumbai presents with a 3-day history of left eye pain, tearing, and photophobia following a minor corneal abrasion from a contact lens. On slit-lamp examination, a branching dendritic ulcer with terminal bulbs and a surrounding halo of edema is seen. Fluorescein staining shows uptake at the ulcer base and margins. Corneal sensation is markedly reduced. The patient reports a history of recurrent 'cold sores' on the lips. What is the most appropriate immediate management?

Explanation

## Management of HSV Epithelial Keratitis ### Clinical Diagnosis: HSV-1 Epithelial Keratitis **Key Point:** The dendritic ulcer with terminal bulbs, reduced corneal sensation, and history of recurrent labial herpes (cold sores) confirm HSV keratitis. The contact lens abrasion was the trigger for viral reactivation. ### Pathophysiology of HSV Keratitis 1. **Reactivation mechanism:** Trauma (abrasion, contact lens) or stress reactivates latent HSV-1 from trigeminal nerve 2. **Epithelial invasion:** Viral replication in corneal epithelial cells 3. **Dendritic ulcer formation:** Infected epithelial cells slough, leaving characteristic branching pattern 4. **Terminal bulbs:** Viral accumulation at ulcer margins 5. **Sensory loss:** Direct viral damage to corneal nerves ### Treatment Algorithm for HSV Epithelial Keratitis ```mermaid flowchart TD A[HSV Epithelial Keratitis Confirmed]:::outcome --> B[Systemic or Topical Antiviral?]:::decision B -->|Uncomplicated epithelial disease| C[Topical Antiviral Only]:::action B -->|Recurrent/Stromal involvement| D[Systemic + Topical]:::action C --> E[Acyclovir ointment 5% OR<br/>Ganciclovir gel 0.15%<br/>5 times daily]:::action D --> F[Systemic acyclovir 400-800 mg<br/>5 times daily<br/>+ Topical agent]:::action E --> G[Add Cycloplegic<br/>for comfort]:::action F --> G G --> H[Avoid Topical Steroids<br/>in Epithelial Disease]:::urgent H --> I[Review at 3-5 days<br/>Expect healing in 7-10 days]:::outcome ``` ### Why Topical Acyclovir Is First-Line Here **High-Yield:** For uncomplicated HSV epithelial keratitis (no stromal involvement, no prior recurrence), topical antiviral monotherapy is standard of care and is more cost-effective than systemic therapy. | Aspect | Topical Acyclovir | Systemic Acyclovir | |--------|-------------------|--------------------| | **Indication** | Epithelial keratitis (uncomplicated) | Recurrent/stromal/immunocompromised | | **Formulation** | 5% ointment or 3% gel | Oral 400–800 mg | | **Frequency** | 5 times daily (every 3–4 hours) | 5 times daily | | **Duration** | 7–10 days | 10–14 days | | **Cost** | Lower | Higher | | **Systemic absorption** | Minimal | Complete | | **Efficacy** | Excellent for epithelial disease | Better for stromal/systemic involvement | **Clinical Pearl:** Topical acyclovir ointment is preferred over gel in India due to better corneal penetration and sustained contact time, though ganciclovir gel is an acceptable alternative. ### Adjunctive Management - **Cycloplegic drops** (e.g., cyclopentolate 1% or tropicamide 1%): Relieves pain from ciliary spasm; use TID–QID - **Preservative-free lubricants:** Support epithelial healing; use frequently - **Contact lens removal:** Mandatory until complete healing - **Avoid topical corticosteroids:** Risk of geographic ulcer expansion (epithelial disease) and stromal melting **Warning:** Topical steroids are CONTRAINDICATED in HSV epithelial keratitis. They suppress local immune response and allow deeper viral invasion → geographic ulcer or stromal keratitis. ### Expected Clinical Course - **3–5 days:** Dendritic ulcer margins begin to clear - **7–10 days:** Complete epithelial healing expected - **Follow-up:** Slit-lamp examination at 3–5 days to confirm healing and rule out stromal involvement **Key Point:** If the ulcer does NOT heal in 10–14 days or shows signs of stromal infiltration, escalate to systemic acyclovir and consider ophthalmology referral.