Most common site of recurrent herpetic keratitis in a patient with previous HSV-1 infection is:

Explanation

## Most Common Site of Recurrent HSV Keratitis **Key Point:** Recurrent herpetic keratitis most commonly affects the corneal epithelium, presenting as dendritiform or geographic ulcers. This is the initial site of viral reactivation and replication. ### Stratification of HSV Keratitis by Depth | Layer | Type | Frequency | Clinical Features | |-------|------|-----------|-------------------| | **Epithelium** | Epithelial keratitis | Most common (60–70%) | Dendritiform ulcer, reduced sensation, rapid healing | | **Stroma** | Stromal keratitis | 20–30% | Disc-shaped infiltrates, vascularization, scarring | | **Descemet + Endothelium** | Endotheliitis | 5–10% | Keratic precipitates, anterior chamber reaction, Busacca nodules | ### Why Epithelium is the Recurrent Site 1. **Viral reactivation pathway:** Latent HSV in trigeminal ganglion → axonal transport to corneal nerve endings → epithelial infection 2. **Epithelial tropism:** HSV has highest replicative capacity in epithelial cells 3. **Accessibility:** Epithelium is the first barrier encountered by reactivating virus 4. **Rapid healing:** Epithelial defects heal within 7–10 days with topical antivirals ### Clinical Presentation of Epithelial Recurrence **High-Yield:** Recurrent epithelial keratitis presents as: - Dendritiform ulcer (classic branching pattern with terminal bulbs) - Or geographic ulcer (larger, map-like ulcer from coalescence of dendrites) - **Reduced corneal sensation** (distinguishes from bacterial or fungal keratitis) - Unilateral, often in same eye as previous episode ### Stromal Involvement (Secondary) **Clinical Pearl:** Stromal keratitis can develop as a sequela of epithelial infection (post-epithelial stromal keratitis) or as an immune-mediated response (immune stromal keratitis). It is less common in recurrent disease and suggests either: - Inadequate epithelial healing - Immune reactivation - Chronic viral persistence ### Management Implications - **Epithelial keratitis:** Topical acyclovir 5× daily; avoid topical steroids (risk of geographic ulcer) - **Stromal keratitis:** Requires topical corticosteroids ± systemic antivirals (immune-mediated component) - **Endotheliitis:** Topical steroids + systemic antivirals; monitor for graft rejection if post-transplant **Warning:** Do not use topical corticosteroids alone in epithelial HSV keratitis—this causes geographic ulceration and worsening of epithelial disease. Always combine with antiviral therapy.