Conjunctivitis — Bacterial vs Viral

The child has a red, goopy eye. The parent wants antibiotic drops immediately — but if this is viral, antibiotics won't help and you'll miss the real teaching moment about hand hygiene.

Conjunctivitis is inflammation of the conjunctiva, categorized by etiology: bacterial, viral, or allergic. Bacterial conjunctivitis: purulent (yellow-green) discharge, eyelid crusting (especially upon waking), starts unilateral but often spreads bilaterally. Common organisms: Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae (children). Treatment: topical antibiotic drops or ointment (erythromycin ointment for routine cases; fluoroquinolone drops are reserved for contact lens wearers or when corneal involvement is a concern). Viral conjunctivitis: watery or clear discharge, associated with URI symptoms (sore throat, rhinorrhea), preauricular lymphadenopathy, highly contagious (adenovirus is the most common cause). Treatment: supportive only — cool compresses, artificial tears, symptom management. Self-limiting in 1–2 weeks. No antibiotic benefit. Allergic conjunctivitis: bilateral, intense itching is the hallmark, watery discharge, seasonal pattern, associated with other allergic symptoms (sneezing, rhinorrhea). Treatment: antihistamine eye drops, mast cell stabilizers, avoid allergens. Ophthalmia neonatorum: conjunctivitis in the first 28 days of life. Gonococcal ophthalmia neonatorum presents with profuse purulent discharge at 2–5 days of life and can rapidly cause corneal perforation and blindness. Prophylaxis: erythromycin 0.5% ophthalmic ointment applied to both eyes of every newborn within 1 hour of birth (even after cesarean delivery). Chlamydial ophthalmia neonatorum presents later (5–14 days) and requires systemic (not topical) treatment. Contact precautions for bacterial and viral conjunctivitis. Nursing: proper eye drop administration technique (pull down lower lid to form a pouch, instill drop without touching the dropper tip to the eye), hand hygiene education, no sharing of towels or pillows, school exclusion for bacterial conjunctivitis until 24 hours on antibiotics (many schools require this), and vision assessment after resolution of infection.

Key Distinctions

Purulent (yellow-green) discharge = bacterial — treat with antibiotics. Watery/clear discharge = viral — supportive care only. This is the fundamental differentiation and the most tested point. Allergic conjunctivitis is distinguished by itching as the predominant symptom and bilateral presentation. Erythromycin eye ointment prophylaxis for newborns prevents gonococcal ophthalmia neonatorum — this is given to ALL newborns, not just those born to mothers with known STIs. Chlamydial ophthalmia neonatorum requires oral azithromycin or erythromycin — topical treatment is insufficient.

Clinical Pearl

Goopy and green — give antibiotics. Watery and weepy — wash hands and wait. The discharge tells you the treatment.