Lit Matters 2: Conjunctivitis: Can we figure out who is bacterial and who is viral?

Acute infectious conjunctivitis is common, and history matters more than discharge color alone. In adults, red eye is usually viral; in children, bacterial causes are more common. The dangerous misses are the painful, photophobic, vision-changing eyes that may be something other than routine conjunctivitis.

Viral Versus Bacterial Conjunctivitis

• Age-based prevalence shift: Adults with acute infectious conjunctivitis are far more likely to have viral disease, while children skew bacterial, a useful pretest frame before you overcall mucopurulent discharge.
• Viral leaning findings: Pharyngitis is the strongest bedside clue toward viral conjunctivitis, with preauricular lymphadenopathy and recent contact with someone with red eye adding diagnostic weight.
• Bacterial leaning findings: Eyelids stuck together on awakening and mucopurulent discharge increase the likelihood of bacterial conjunctivitis, and otitis media is a particularly helpful clue in children.
• Discharge is imperfect: Watery does not rule out bacterial and purulent does not rule out viral; roughly 1 in 5 viral cases had purulence, a nuance we get into in the episode.
• Watchful waiting option: Most uncomplicated bacterial conjunctivitis improves within 1 to 2 days even without antibiotics, making delayed prescribing or outpatient follow-up a reasonable strategy.
• Serious red eye warnings: Decreased visual acuity, significant pain, or severe photophobia should push you away from routine conjunctivitis and toward a more dangerous ocular diagnosis.