Conjunctivitis, Acute



Inflammation of the bulbar and/or palpebral conjunctiva of <4 weeks’ duration

Geriatric Considerations

  • Suspect bacterial, autoimmune, or irritative process.
  • If purulent, risk of bacterial cause increases with age and long-term care facility residence, with age >65 years and bilateral lid adherence. Risk for bacterial infection is >70%.

Pediatric Considerations
Neonatal conjunctivitis may be gonococcal, chlamydial, irritative, or related to dacryocystitis. Children <5 years of age are more likely to have bacterial involvement than adults, but most self-resolve in 2 to 5 days. Despite lack of evidence, some daycare regulations may require a child with presumed conjunctivitis to be treated with a topical antibiotic before returning.


  • Predominant age
    • Pediatric: viral, bacterial, irritant; adult: bacterial, viral, allergic, irritant
  • Predominant sex: male = female

1–2% of ambulatory office visits, up to 3% of ER visits

Etiology and Pathophysiology

  • Viral
    • Adenovirus (common cold), coxsackievirus; enterovirus (acute hemorrhagic conjunctivitis); herpes simplex; herpes zoster or varicella; measles, mumps, or influenza; SARS-CoV-2
  • Bacterial
    • Staphylococcus aureus, MRSA or Staphylococcus epidermidis; Streptococcus pneumoniae; Haemophilus influenzae (children)
    • Pseudomonas spp. or anaerobes (contact lenses users); Acanthamoeba-contaminated contact lenses solution (rare; ~30 cases/year in the United States); Neisseria gonorrhoeae; Chlamydia trachomatis: gradual onset 1 to 4 weeks
  • Allergic
    • Hay fever, seasonal allergies, atopy
  • Nonspecific
    • Irritative: topical medications, wind, dry eye, UV light exposure, smoke, chlorine
    • Autoimmune: Sjögren syndrome, pemphigoid, Wegener granulomatosis, Reiter syndrome, sarcoid

Risk Factors

  • History of contact with infected persons; sexually transmitted disease (STD) contact: gonococcal, chlamydial, syphilis, or herpes; contact lenses: pseudomonal or acanthamoeba keratitis
  • Epidemic bacterial (streptococcal) conjunctivitis reported in school settings, epidemic adenoviral transmission in crowded settings, MRSA in long-term care facilities

General Prevention

  • Wash hands frequently.
  • Eyedropper technique: while eye is closed and head back, several drops over nasal canthus and then open the eyes to allow liquid to enter; never touch the tip of the dropper to skin or eye.

Commonly Associated Conditions

Viral infection (e.g., common cold); possible sexually transmitted infection

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