Viral Conjunctivitis

Etiology

Clinical Variants

1. Non-specific Acute Follicular Conjunctivitis

2. Pharyngoconjunctival Fever (PCF)

• Adenovirus serovars 3, 4, 7
• Spread by droplets in family clusters with upper respiratory tract infections
• Fever + prominent sore throat + conjunctivitis + preauricular lymphadenopathy
• Keratitis in ~30% (usually not severe)

3. Epidemic Keratoconjunctivitis (EKC)

• Adenovirus serovars 8, 19, 37; the most severe form
• Marked keratitis in ~80%; photophobia can be prominent
• Subepithelial infiltrates (SEIs) develop 1-2 weeks post-onset
• May cause significant visual morbidity; pseudomembranes can form

4. Acute Hemorrhagic Conjunctivitis

• Enterovirus 70, Coxsackievirus A24; more common in tropical regions
• Rapid onset, prominent subconjunctival hemorrhages, chemosis
• Resolves in 1-2 weeks; enterovirus 70 is rarely followed by a polio-like paralysis

5. Chronic/Relapsing Adenoviral Conjunctivitis

• Rare; chronic non-specific follicular/papillary picture persisting over years; eventually self-limiting

Signs & Symptoms

• Inferior palpebral conjunctival follicles (lymphocyte aggregations around vessels)
• Tender palpable preauricular lymph node

• Watery (not purulent) discharge
• Red, edematous eyelids
• Petechial subconjunctival hemorrhages
• Punctate keratopathy / epithelial erosions in severe cases
• Membranes or pseudomembranes (severe inflammation)
• Fine intraepithelial microcysts (early corneal sign helpful in diagnosis)
• SEIs (subepithelial infiltrates) developing 1-2 weeks after onset, possibly persisting for months to years

Fig: Adenoviral keratoconjunctivitis - follicular conjunctivitis with subconjunctival hemorrhage (Kanski's Clinical Ophthalmology)

Fig: Pseudomembrane on the palpebral conjunctiva in severe adenoviral conjunctivitis (Kanski's Clinical Ophthalmology)

Fig: Corneal subepithelial infiltrates (SEIs) stained with fluorescein - a complication of adenoviral EKC (Kanski's Clinical Ophthalmology)

Fig: Adenoviral conjunctivitis in a child (Tintinalli's Emergency Medicine)

Investigation

• PCR (NAAT) - sensitive and specific for viral DNA; preferred
• Point-of-care immunochromatography - detects adenoviral antigen in tears in 10 minutes; excellent sensitivity and specificity
• Giemsa stain - predominantly mononuclear cells in adenoviral infection; multinucleated giant cells in HSV
• Viral culture - reference standard but slow (days to weeks) and expensive
• Serology (IgM/rising IgG) - rarely used in practice
• Consider testing for chlamydia in non-resolving cases

Treatment

Supportive (all viral conjunctivitis)

1. Counsel the patient: self-limited, typically worsens for first 4-7 days, may take 2-3 weeks to resolve (longer with corneal involvement)
2. Preservative-free artificial tears 4-8x/day; single-use vials reduce transmission
3. Cool compresses several times per day for symptomatic relief
4. Topical antihistamines (e.g., epinastine 0.05% b.i.d.) if itching is severe
5. Discontinue contact lens wear until full resolution

Do NOT prescribe

• Topical antibiotics are not indicated - no evidence of protection against secondary infection, and there is suspicion of harm. Use only if secondary bacterial infection is confirmed or corneal erosions are present.

For Membranes/Pseudomembranes

• Gently peel with a cotton-tip applicator or smooth forceps to improve comfort, reduce corneal defects, and prevent symblepharon
• Topical steroids: loteprednol 0.5% or prednisolone acetate 1% q.i.d. (more frequent/stronger dose)
• Consider steroid ointment (e.g., fluorometholone 0.1% ointment q.i.d.) when significant tearing would reduce drop exposure time

For SEIs Reducing Vision / Causing Photophobia

• Weaker steroid at lower frequency: loteprednol 0.2% or 0.5% b.i.d.
• Caution: Steroids may hasten symptom resolution but prolong the infectious period and necessitate long-term taper; SEIs often recur during/after taper. Do not prescribe without slit-lamp examination. Monitor IOP if prolonged use.
• NSAIDs have unclear benefit but may help during steroid weaning without promoting viral replication

Infection Control

• Contagious for 10-12 days from onset (while eyes are red/discharging)
• Meticulous hand hygiene; avoid eye rubbing, towel/pillow sharing
• Restrict work/school during active infection
• Disinfect instruments and surfaces with sodium hypochlorite or povidone-iodine
• Povidone-iodine is effective against free adenovirus and may reduce infectivity

Follow-up

• Routine: 2-3 weeks
• Sooner if worsening significantly or if topical steroids are prescribed

Key Differentiating Features from Bacterial Conjunctivitis