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Inflammation of the conjunctiva is commonly infective or allergic. It is usually unilateral.

  • it is the commonest cause of red eye (1)
  • conjunctivitis in children is predominantly bacterial, with nontypeable H. influenzae being the most common organism (2)

Clinical features depend on the underlying cause

  • however, the eyes often feel gritty or in allergic conjunctivitis, itchy
  • discharge is a constant finding and may be purulent, mucoid or watery; typically, the eyelashes are stuck together on waking
  • may be transient blurring as a consequence of discharge smearing the cornea but this is easily cleared by blinking
  • photophobia and pain indicate corneal involvement - keratoconjunctivitis - which is not infrequent
  • diffuse hyperaemia overlying the sclera and the inner surface of the eyelids.
  • viral infection is associated with follicles; allergies, with chemosis.

Itching suggests an allergic cause (3).

Infective conjunctivitis is treated with topical antibiotics; non-infective with anti-inflammatory agents.

  • a meta-analysis concluded that '..acute conjunctivitis seen in primary care can be thought of as a self-limiting condition, with most patients getting better regardless of antibiotic therapy. Patients with purulent discharge or a mild severity of red eye may have a small benefit from antibiotics...' (4)


  1. Leibowitz HM. The Red Eye Leibowitz HM. NEJM 2000; 343:345.
  2. Patel PB et al. Clinical features of bacterial conjunctivitis in children. Acad Emerg Med. 2007 Jan;14(1):1-5.
  3. Rietveld RP et al. Predicting bacterial cause in infectious conjunctivitis: cohort study on informativeness of combinations of signs and symptoms. BMJ 2004 329: 206-210.
  4. Jefferis Jet al. Acute infective conjunctivitis in primary care: who needs antibiotics? An individual patient data meta-analysis. Br J Gen Pract. 2011 Sep;61(590):e542-8. doi: 10.3399/bjgp11X593811.

Last reviewed 06/2022