FFinalistSouthampton · 2027
Ophthalmology
AKT · Ophthalmology/Cornea & ant. segment

Herpes simplex keratitis

HSV-1 epithelial (dendritic) keratitis ± stromal disease

Overview

Corneal infection by herpes simplex virus, classically an epithelial dendritic ulcer (branching, terminal end-bulbs) that stains with fluorescein, often recurrent and unilateral with reduced corneal sensation. Treated with topical/oral antivirals; topical steroids alone are dangerous and can cause a geographic ulcer.

Recognise

  • Unilateral painful red eye, photophobia, watering, foreign-body sensation, often recurrent
  • DENDRITIC ulcer with terminal bulbs on fluorescein staining (rose bengal stains the edges)
  • Reduced corneal sensation; may progress to stromal keratitis (immune, with stromal haze/oedema)

Red flags

  • Steroid use on an undiagnosed dendrite → geographic ulcer (sight-threatening) — fluorescein every red eye before steroids
  • Disciform/stromal keratitis with reduced vision → specialist antiviral + cautious steroid

Differentials & how to tell them apart

Herpes zoster ophthalmicuspseudodendrites (no end-bulbs), V1 vesicular rash, Hutchinson sign
Acanthamoeba keratitiscontact-lens wearer, pain out of proportion, ring infiltrate
Bacterial keratitisstromal infiltrate/hypopyon rather than a branching epithelial ulcer
Recurrent corneal erosionrecurrent pain without a true dendrite
HSV keratitis — branching dendritic ulcer on fluorescein

HSV keratitis — branching dendritic ulcer on fluorescein

Imrankabirhossain / CC BY-SA 4.0 — Wikimedia Commons

Investigations

Clinical (fluorescein dendrite, reduced corneal sensation). Corneal swab/PCR or scraping in doubt. Slit-lamp.

Management

Topical (± oral) antiviral; refer same-day — avoid steroids

  1. 1Refer to emergency eye service same-day. Topical antiviral (aciclovir/ganciclovir) for epithelial keratitis ± oral aciclovir; avoid contact lenses.Gate: NEVER give topical steroids for an undiagnosed/epithelial dendrite — they cause a geographic ulcer; steroids are only added by a specialist, with antiviral cover, for stromal disease
  2. 2Stromal/disciform keratitis → specialist topical steroid + antiviral; recurrent disease → long-term oral aciclovir prophylaxis; corneal scarring → keratoplasty.
Topical antiviral (aciclovir/ganciclovir ointment) — epithelial keratitis — first-line
Oral aciclovir — for epithelial disease, immunocompromised, or prophylaxis of recurrence
Topical steroid — ONLY specialist, with antiviral cover — for stromal/disciform disease; never for an untreated epithelial dendrite

Key points

Branching dendrite + reduced corneal sensation + recurrent unilateral red eye = HSV. The exam point is: fluorescein every red eye and never steroid a dendrite.

Monitor & prognosis

Recurrence is common; track corneal sensation/scarring.

Epithelial disease heals; recurrent stromal disease scars and can need grafting.

Source: NICE CKS Herpes simplex – ocular; College of Optometrists CMG