Skip to Main Content

Key Features

Essentials of Diagnosis

  • The most common eye disease, also known as "pink eye"

  • Red palpebral conjunctiva

  • Usually mild to moderate ocular irritation and discharge, clear cornea, and normal visual acuity

General Considerations

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

  • Other common causes include atopy, chemical irritants, and keratoconjunctivitis sicca (dry eyes), and deliberate self-harm

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


  • 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

  • Keratoconjunctivitis sicca is common in elderly women and sometimes associated with systemic diseases (Sjögren syndrome)

  • 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

  • No blurring of vision; only mild discomfort

  • 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, often with marked foreign body sensation and a follicular conjunctivitis

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

  • Herpes simplex virus (HSV) is another cause

    • Usually unilateral infection

    • May be associated with lid vesicles

  • Enterovirus 70 or coxsackievirus A24 characteristically cause acute hemorrhagic conjunctivitis

Keratoconjunctivitis sicca

  • Due to hypofunction of the lacrimal glands, excessive evaporation of tears, abnormalities of the lipid component of tears, or mucin deficiency

  • Ocular dryness, redness, or foreign body sensation

  • Marked discomfort, photophobia, and excessive mucus in severe cases

  • Corneal ulceration may develop

Allergic eye disease

  • Itching, tearing, redness, stringy discharge; ...

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.