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

Demographics

• 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

• 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 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 ...