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Infective Conjunctivitis

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Overview

Infective conjunctivitis is the inflammation of the conjunctiva secondary to infection. This is often bacterial conjunctivitis or viral conjunctivitis. Viral conjunctivitis is generally more prolonged. Herpes viruses can cause keratitis and uveitis.

Causes

Bacterial conjunctivitis

The most common causes are:

  • Staphylococcus aureus
  • Staphylococcus epidermidis
  • Streptococcal pneumoniae
  • Haemophilus influenzae – more common in children

Other causes can be:

  • Neisseria gonorrhoeae:
    • Symptom onset is usually within 12-24 hours
    • There are usually copious amounts of discharge with pus
    • Pre-auricular lymphadenopathy may be present
    • Can invade the cornea and lead to globe perforation and visual impairment
    • If this is seen in a child, sexual abuse must be ruled out
  • Chlamydia trachomatis:
    • There may be green-stringy discharge in the morning
    • Pre-auricular lymphadenopathy may be present
    • May cause corneal ulceration and scarring leading to visual impairment
    • If this is seen in a child, sexual abuse must be ruled out

Viral conjunctivitis

  • Most commonly due to adenovirus
  • Herpes viruses may cause conjunctivitis:
    • Herpes simplex – unilateral red eye with vesicular eyelid lesions
    • Herpes zoster – lesions on the tip of the nose (Hutchinson’s sign)

Epidemiology

  • In adults, viral conjunctivitis is more common than bacterial conjunctivitis
  • In children, bacterial conjunctivitis is more common than viral conjunctivitis

Risk Factors

  • Current/recent upper respiratory tract infection
  • Infection in one eye – the infection can spread to the other
  • Exposure to an infected person
  • Contact lens use
  • Previous infection with Herpes simplex virus
  • In neonates after vaginal delivery

Presentation

Features that suggest bacterial conjunctivitis are:

  • Purulent discharge
  • Sticky eyes – patients often find that their eyes are stuck together in the morning
  • Unilateral features are more suggestive of a bacterial cause

Features that suggest viral conjunctivitis are:

  • Watery discharge
  • Preauricular lymphadenopathy
  • Recent upper respiratory tract infection

Examination may show:

  • Red eyes
  • Chemosis – swelling of the conjunctiva
  • Swollen eyelids

Differential Diagnoses

Dry eye

  • Symptoms are more chronic
  • There may be minimal/no discharge
  • No redness
  • No lymphadenopathy

Blepharitis

  • Usually bilateral symptoms
  • There may be minimal/no discharge
  • There may be eyelid margin redness

Anterior uveitis

  • Pain and photosensitivity are more prominent features than irritation
  • More commonly unilateral

Investigations

  • Diagnosis is usually clinical and swabs are not routinely taken, however:
    • Swabs can be considered if patients do not respond to initial treatment but do not need to be referred to secondary care
    • Swabs are taken in neonates or cases where gonococcal/chlamydial infection is suspected
  • Referral to secondary care for urgent swabs and microbiological investigation:
    • Ordered in neonates or people with features of gonococcal or chlamydial infection

Management

Acute bacterial conjunctivitis

  • 1st-line: conservative measures
    • Most cases are self-limiting and resolve within 5-7 days without treatment
    • Cleaning the eyelids in boiled and cooled water with diluted baby shampoo can help
  • 2nd-line: antibiotic eyedrops if symptoms are severe/rapid resolution required
    • Options are chloramphenicol or fusidic acid

Acute viral (non-herpetic) conjunctivitis

  • 1st-line: conservative measures
    • Most cases are self-limiting and resolve within 1-2 weeks without treatment
    • Cleaning the eyelids in boiled and cooled water with diluted baby shampoo can help
  • If the patient returns with symptoms, consider adenovirus and Herpes simplex PCR and bacterial culture + empirical antibiotic eyedrops e.g. topical chloramphenicol or topical fusidic acid
  • Other scenarios
  • Gonococcal/chlamydial conjunctivitis: treat respective infection
  • Neonatal conjunctivitis: immediate ophthalmology referral

Monitoring

  • Consider ophthalmology referral if symptoms persist for more than 7-10 days after starting treatment
  • Patients with gonococcal/chlamydial conjunctivitis should be followed up more closely

Patient Advice

  • Patients should be advised that infective conjunctivitis is contagious and they should try to prevent spread though washing hands frequently with soap and water, using separate towels, and avoiding close contact with others
    • School exclusion is not necessary
  • Patients wearing contact lenses should immediately stop during the duration of illness and treatment

Complications

  • Bacterial conjunctivitis can cause keratitis in people who wear contact lenses or if they are compromised
  • Gonococcal conjunctivitis has a high risk of corneal perforation
  • Infective conjunctivitis in neonates can cause complications such as corneal neovascularisation, scarring, pneumonia, globe perforation, and blindness

Prognosis

  • Viral conjunctivitis – most cases resolve in around 7 days
  • Bacterial conjunctivitis – most cases resolve within 5-10 days
  • Neonatal conjunctivitis – most cases are mild but untreated infections can have serious consequences

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