Highly contagious viral inflammation of conjunctiva — typically adenovirus; supportive care only.
Also known as: viral conjunctivitis, pink eye viral, adenoviral conjunctivitis, epidemic keratoconjunctivitis, EKC
Overview
Self-limited inflammation of the conjunctiva caused by a virus, most often adenovirus. Subtypes include pharyngoconjunctival fever (adenovirus 3, 7), epidemic keratoconjunctivitis (EKC, adenovirus 8, 19, 37 — corneal involvement), HSV/VZV conjunctivitis, and enterovirus 70 acute hemorrhagic conjunctivitis.
Epidemiology
Most common type of infectious conjunctivitis in adults. Highly contagious by direct contact and fomites; outbreaks occur in schools, camps, military barracks, healthcare facilities. Incubation 5-12 days; contagious during symptoms and up to 14 days after onset.
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Healthcare exposure (notable in clinics with shared instruments — tonometer prisms)
Recent ocular trauma or surgery (HSV reactivation)
Pathophysiology
Adenoviral infection of conjunctival epithelium leads to lymphocyte and macrophage infiltration. EKC involves additional invasion of corneal epithelium and subepithelial stroma, leading to characteristic subepithelial corneal infiltrates that can persist for months. HSV ocular infection typically produces dendritic keratitis with conjunctivitis. Enterovirus 70 produces subconjunctival hemorrhages with bilateral conjunctivitis.
Clinical presentation
Symptoms
Acute red eye, often beginning unilateral and spreading to fellow eye within days
Watery discharge — clear, profuse
Foreign body or gritty sensation, burning
Mild eyelid swelling and crusting (less than bacterial)
Photophobia and decreased vision suggest corneal involvement (EKC, HSV)
Signs / physical exam
Diffuse bulbar conjunctival injection with follicular reaction on tarsal conjunctiva
Watery, sometimes mucoid, discharge
Tender preauricular lymphadenopathy — characteristic of viral and gonococcal conjunctivitis
Punctate keratitis or subepithelial corneal infiltrates in EKC (slit lamp)
Pseudomembrane on tarsal conjunctiva in severe EKC
Dendritic corneal ulcer on fluorescein staining → HSV (treat with antivirals; AVOID corticosteroids)
Classic findings
Watery red eye with follicular reaction, ipsilateral preauricular lymphadenopathy, and recent URI in an adult.
Differential diagnosis
Bacterial conjunctivitis — Purulent discharge throughout day, eyelids matted shut on awakening, minimal itching, no preauricular node
Allergic conjunctivitis — Itching is hallmark, bilateral, watery discharge with stringy mucus, atopic history, chemosis
HSV keratoconjunctivitis — Dendritic ulcer on fluorescein staining, vesicles on lid, decreased corneal sensation; topical and/or oral antivirals; do NOT give topical steroid empirically
Severe conjunctivitis, subepithelial corneal infiltrates, pseudomembranes
Supportive ± steroids by ophthalmology
HSV keratoconjunctivitis
Dendritic ulcer on fluorescein, unilateral
Topical/oral antivirals; AVOID empiric steroids
Herpes zoster ophthalmicus (VZV)
V1 vesicles, Hutchinson sign
Oral acyclovir/valacyclovir; ophthalmology
Acute hemorrhagic conjunctivitis (enterovirus 70)
Subconjunctival hemorrhages, bilateral
Supportive
Common viral conjunctivitis subtypes and their distinguishing features.
Treatment
First-line
Supportive care — viral conjunctivitis is self-limited (1-3 weeks)
Cool compresses to reduce swelling
Artificial tears for lubrication and symptom relief
Strict hygiene: hand washing, no shared towels/pillows/eye drops, no cosmetics, no contact lens wear until resolved
Stay home from school/work until tearing and discharge resolve (typically 7-14 days)
Discard contact lenses and case after recovery
Second-line / adjunct
HSV keratoconjunctivitis: trifluridine 1% drops 9×/day OR ganciclovir 0.15% gel 5×/day OR oral acyclovir 400 mg 5×/day; ophthalmology referral; do NOT give empiric topical corticosteroids — they can worsen HSV epithelial keratitis
Severe EKC with pseudomembranes or visually significant subepithelial infiltrates: topical corticosteroids ONLY under ophthalmologist direction (HSV must be excluded)
Avoid topical antibiotics — no benefit in viral disease and contribute to resistance
Ophthalmology referral for: HSV/VZV, contact lens wear, severe symptoms, decreased vision, photophobia, no improvement after 7-10 days
Complications
Spread to fellow eye and household/work contacts
Subepithelial corneal infiltrates with persistent blurred vision (EKC) — months
Symblepharon (conjunctival scarring) with pseudomembranes
HSV stromal keratitis and recurrent disease with vision loss
Bacterial superinfection (rare)
Healthcare-associated outbreaks if equipment not disinfected (tonometer prisms)
PANCE pearls
Tender preauricular lymphadenopathy supports viral (or gonococcal) etiology — usually absent in routine bacterial or allergic.
Epidemic keratoconjunctivitis (EKC) — highly contagious; subepithelial corneal infiltrates can blur vision for months. Quarantine and disinfect equipment with bleach (alcohol does NOT kill adenovirus).
Dendritic ulcer on fluorescein staining = HSV keratitis — antivirals, NEVER empiric topical steroids.
Hutchinson sign (vesicle on nasal tip) heralds ocular involvement in herpes zoster ophthalmicus — urgent ophthalmology consult.
Hand washing and not sharing towels are the most effective measures to prevent spread.
References
AAO 2018 — American Academy of Ophthalmology. Conjunctivitis Preferred Practice Pattern. Ophthalmology 2019;126(1):P94-P169
CDC — Centers for Disease Control and Prevention. Adenovirus and Healthcare-Associated Conjunctivitis Outbreaks. 2022
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