A 35-year-old man with a history of recurrent cold sores presents with left eye pain, photophobia, and blurred vision for 3 days. Visual acuity is 6/12. Slit-lamp examination reveals a branching dendritic ulcer with terminal bulbs on the cornea, staining with fluorescein at the ulcer base and edges. There is mild anterior chamber reaction. He has no skin vesicles currently, but reports a history of perioral herpes. What is the most appropriate initial management?

Explanation

## Management of Herpes Simplex Epithelial Keratitis (HSK) ### Clinical Diagnosis **Key Point:** The branching dendritic ulcer with terminal bulbs staining with fluorescein, combined with a history of recurrent perioral herpes (HSV-1), is **pathognomonic for HSV epithelial keratitis**. This is an immunocompetent adult with uncomplicated epithelial HSK. ### Why Topical Acyclovir + Cycloplegia Is the Correct First-Line Treatment **High-Yield (Kanski's Clinical Ophthalmology / AAO Guidelines):** For uncomplicated HSV epithelial keratitis in an immunocompetent patient, **topical antiviral therapy is the mainstay of treatment**. Systemic acyclovir is NOT routinely required for isolated epithelial disease in immunocompetent individuals — it is reserved for: - Severe or bilateral disease - Immunocompromised patients - Stromal or endothelial involvement - Recurrent disease with high frequency | Treatment Component | Rationale | |---------------------|-----------| | **Topical acyclovir ointment 3% — 5× daily** | Direct delivery to corneal epithelium; achieves high local concentrations; first-line per AAO and UK guidelines | | **Cycloplegic agents (e.g., cyclopentolate 1%)** | Relieves ciliary spasm causing pain; prevents posterior synechiae given mild anterior chamber reaction | | **NO topical corticosteroids** | Absolutely contraindicated in active epithelial HSK — accelerates viral replication, risks geographic ulcer and corneal perforation | ### Why Systemic Acyclovir Is NOT Routinely Required Here The HEDS (Herpetic Eye Disease Study) trials demonstrated that **systemic acyclovir did not significantly improve outcomes in epithelial keratitis** compared to topical therapy alone in immunocompetent patients. Systemic therapy adds cost, systemic side effects, and is not standard first-line for isolated epithelial disease. Option A's claim that systemic + topical is the "gold standard" for epithelial HSK is not supported by current evidence-based guidelines. ### Pathophysiology of HSV Epithelial Keratitis 1. HSV-1 reactivates from the trigeminal ganglion → travels to cornea 2. Viral replication destroys corneal epithelial cells → dendritic ulcer 3. Terminal bulbs = swollen nerve endings (distinguishes HSV from other dendrites) 4. Fluorescein stains ulcer base (dead epithelium); rose bengal/lissamine green stains infected margins 5. Without treatment: geographic ulcer → stromal involvement → scarring ### Critical Contraindication: Topical Corticosteroids in Epithelial HSK **Warning:** Option C (topical ganciclovir + dexamethasone) is dangerous. Topical corticosteroids in epithelial HSK: - Suppress local immune response - Accelerate viral replication - Cause **geographic ulcer** (coalescence of dendrites) - Risk corneal perforation and permanent scarring **Clinical Pearl (Kanski):** Topical corticosteroids are indicated ONLY in stromal or endothelial HSK (immune-mediated), and ONLY under close ophthalmology supervision with concurrent antiviral cover. ### Why Other Options Are Wrong - **Option A:** Systemic acyclovir is not standard first-line for uncomplicated epithelial HSK in immunocompetent patients (HEDS trial evidence); topical therapy alone is sufficient. Also, Option A omits cycloplegia despite the anterior chamber reaction noted in the stem. - **Option C:** Adding topical dexamethasone to active epithelial HSK is contraindicated — risks geographic ulcer and perforation. - **Option D:** Observation without antiviral therapy risks progression to geographic ulcer, stromal involvement, and permanent corneal scarring. Antiviral therapy is mandatory. ### Expected Course with Topical Acyclovir - **Days 1–3:** Ulcer may slightly enlarge before improvement - **Days 4–7:** Epithelial healing begins - **Days 7–14:** Complete epithelial healing expected - **Post-healing:** Monitor for recurrence; consider prophylactic oral acyclovir if recurrences are frequent (≥2/year) **Reference:** Kanski's Clinical Ophthalmology, 9th ed.; AAO Preferred Practice Pattern — Herpes Simplex Virus Keratitis; HEDS Trial (Arch Ophthalmol, 2000).