Conjunctivitis can be bacterial, viral or allergic



  • May be unilateral or bilateral
  • There is usually a mucopurulent discharge and the lashes are stuck together on waking
  • In bacterial conjunctivitis, discharge may continue throughout the day, whereas in viral conjunctivitis the affected eye(s) tend to be stuck together on waking, but water in the daytime
  • There is a gritty/burning discomfort, rather than pain
  • Blurring of vision is usually due to disturbance of the tear film, which clears with blinking
  • Persistent blurred vision may indicate the development of corneal involvement
  • Viral conjunctivitis is associated with sore throat and tender preauricular lymph nodes
  • Bilateral itching and watery discharge, especially if seasonal, suggests allergic conjunctivitis 



  • Redness due to dilated conjunctival vessels affects all conjunctiva (globe of eye and tarsal conjunctiva lining inside of eyelids) in contrast to uveitis or scleritis where redness is only on the globe
  • Purulent discharge suggests bacterial origin
  • Small white corneal infiltrates can occur in viral infection 


Eye examination

  • Instil 1 drop of proxymetacaine 0.5% with fluorescein 0.25%
  • Look for multiple fine white spots or fluorescein stains on cornea; major corneal  staining or clouding suggests an alternative diagnosis e.g. corneal ulcer



  • Chloramphenicol eye drops qds for bacterial conjunctivitis
  • Topical lubricants for viral conjunctivitis
  • Viral conjunctivitis is spread by droplet infection and there is an increased risk of spread in any situation where people are in regular close contact; the risk of spread can be reduced by careful hand-washing and rigorous hygiene (e.g. use of separate towels)
  • Topical steroids for corneal infiltrates should be prescribed by an ophthalmologist
  • Antihistamine or anti-mast cell drops (e.g. cromoglycate, nedocromil, opatanol ) are used for allergy


Last updated: November 2017