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For further information, see CMDT Part 7-06: Conjunctivitis

Key Features

Essentials of Diagnosis

  • Inflammation of the mucous membrane that lines the surface of the eyeball and inner eyelids

  • May be acute or chronic

  • Must be differentiated from acute uveitis, acute glaucoma, and corneal disorders

General Considerations

  • Usually due to bacterial (including gonococcal or chlamydial) or viral infections

  • Other common causes include atopy, chemical irritants, dry eyes, and trauma

  • Dry eye (keratoconjunctivitis sicca) describes a condition of tear film instability and associated ocular and visual complaints

    • Hypofunction of the lacrimal glands causes loss of the aqueous component of tears

    • Abnormalities of the lipid component of tears or mucin deficiency causes excessive evaporation of tears

  • Mode of transmission of infectious conjunctivitis is usually direct contact via fingers or objects to the other eye or to other persons

  • May also be spread through respiratory secretions or contaminated eye drops


  • Precise incidence is unknown but very common

  • Men and women affected equally

  • Age group affected depends on the underlying cause

  • Trachoma (Chlamydia trachomatis) is a major cause of blindness worldwide

  • Gonococcal conjunctivitis and inclusion conjunctivitis are caused by the agents involved in the respective genital tract diseases (Neisseria gonorrhoeae or C trachomatis) and typically occur in sexually active adults

  • Viral conjunctivitis is more common in children than adults, with contaminated swimming pools or ophthalmologists' offices often being the source of epidemics

  • Dry eye

    • Increases with age and female sex

    • May be due to hereditary disorders, systemic disease (eg, Sjögren syndrome), or systemic drugs

  • Allergic eye disease typically begins in late childhood or young adulthood

Clinical Findings

Symptoms and Signs

Bacterial conjunctivitis

  • Staphylococci (including methicillin-resistant S aureus), streptococci, Haemophilus, Pseudomonas, and Moraxella are the most common organisms isolated

  • Purulent discharge

  • Eyelid matting

  • Blurring of vision and discomfort are mild

  • Usually self-limited, lasting 10–14 days if untreated

Gonococcal conjunctivitis

  • Exposure to infected genital secretions is the usual mode of transmission

  • Copious purulent discharge

  • An ophthalmologic emergency because corneal involvement may rapidly lead to perforation

Chlamydial conjunctivitis

  • Recurrent episodes of infection in childhood manifest as bilateral follicular conjunctivitis, epithelial keratitis, and corneal vascularization (pannus)

  • Scarring (cicatrization) of the tarsal conjunctiva leads to entropion and trichiasis in adulthood, with secondary central corneal scarring

  • Inclusion conjunctivitis produces follicular conjunctivitis with mild keratitis, redness, discharge, irritation, and nontender preauricular lymphadenopathy

Viral conjunctivitis

  • Adenovirus is the most common cause

    • Bilateral infection with copious watery discharge and a follicular conjunctivitis

    • There may be pharyngitis, fever, malaise, and preauricular adenopathy

  • Herpes simplex virus (HSV) is another cause

    • Usually unilateral infection

    • May ...

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