Acute Bacterial Conjunctivitis

Acute bacterial conjunctivitis is infection of the conjunctiva by bacteria, usually self-limiting within 1 to 2 weeks.

• Adults: Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis.
• Children: H. influenzae, S. pneumoniae, M. catarrhalis (conjunctivitis otitis syndrome with H. influenzae).
• Transmission by direct contact and fomites; outbreaks occur in schools and households.
• Contact lens wearers: consider Pseudomonas aeruginosa, which can progress to keratitis.
• Hyperacute purulent forms (Neisseria gonorrhoeae, N. meningitidis) are vision threatening.

• Redness, grittiness, mucopurulent discharge with lids stuck together on waking, usually starting in one eye and spreading to the other within days.
• Papillary reaction, mild chemosis, lid oedema, conjunctival injection greatest in the fornices.
• Vision is normal or only transiently blurred by discharge; cornea clear; no significant photophobia or pain.
• Marked purulence, severe chemosis, preauricular nodes and rapid onset within 12 to 24 hours suggest gonococcal infection.
• Red flags: reduced vision, severe pain, photophobia, corneal infiltrate, contact lens use, immunosuppression, neonate.

• Clinical diagnosis in most cases.
• Conjunctival swab for Gram stain and culture in severe, hyperacute, neonatal, recurrent, contact lens related or treatment failure cases; nucleic acid amplification for gonococcus and chlamydia.
• Fluorescein staining to exclude corneal involvement.
• Differentiate from viral conjunctivitis (watery discharge, follicles, preauricular node) and allergic conjunctivitis (itch, stringy mucus).

• Mild cases resolve without antibiotics in 5 to 7 days; lid hygiene, cool compresses, artificial tears.
• Topical antibiotics shorten the course: chloramphenicol 0.5 percent drops every 2 to 3 hours for 2 days then four times daily for 5 days, or fusidic acid 1 percent gel twice daily, or ofloxacin 0.3 percent drops four times daily, or moxifloxacin 0.5 percent drops three times daily, for 5 to 7 days, or azithromycin 1.5 percent drops twice daily for 3 days.
• Contact lens wearers: stop lens wear and use a fluoroquinolone with antipseudomonal cover (ofloxacin 0.3 percent or ciprofloxacin 0.3 percent four times daily).
• Hyperacute or gonococcal disease: ceftriaxone 1 g intramuscularly as a single dose plus azithromycin 1 g orally as a single dose. Irrigate the conjunctival sac with saline every hour until the discharge clears, and treat sexual contacts.
• Hygiene: separate towels, hand washing, no eye make up, return to school after 24 hours of therapy or when discharge resolves.
• Review if no improvement within 48 to 72 hours: reculture and reassess for keratitis, chlamydia, or viral cause.