conjunctivitis
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Table of Contents
conjunctivitis
Introduction
- bilateral red eyes tend to be more likely due to either conjunctivitis, welder flash burns - UV keratopathy (photo keratitis), or chemical burns, the latter two generally also cause keratitis
- if only one eye is red, take special care to exclude other important pathologies - see acute atraumatic painful red eye(s)
- conjunctivitis may be caused by highly contagious organisms such as adenovirus, Haemophilus influenzae, etc - wear gloves and wash hands!
- spread is usually via direct contact and indirect contact (eg. toys, door handles, etc)
- a person with infectious conjunctivitis will remain infectious as long as there is a discharge from their eye
- children with infectious conjunctivitis should be kept home from child care, kindergarten or school until the discharge from the eyes has cleared1)
- regularly wash hands thoroughly to prevent the infection spreading to others
- use a clean pillowcase and towel to use each day to prevent the infection spreading to the other eye if only one is affected
- breastmilk used on the eyes does not treat conjunctivitis and there is no benefit to using it on your baby’s eyes
- in addition, respiratory viruses are spread by droplets / aerosol from sneezing or coughing
- those who wear contact lenses should not use them until their conjunctivitis has cleared up
Clinical features
- usually present with bilateral itchy, mildly painful eyes with swollen, injected conjunctiva
- visual acuity may be affected if there is a lot of tearing
- infective causes generally start in one eye and spread to the other eye
- bacterial causes tend to have a purulent discharge
Aetiology
viral
- respiratory viruses - common cold, influenza, COVID-19 coronavirus (2019-nCoV / SARS-CoV-2)
- enteroviruses
- picornaviruses
bacterial
- Staphylococcus aureus
- common in adults; spreads easily via skin-to-eye contact
- Streptococcus pneumoniae
- frequently causes outbreaks among children
- Haemophilus influenzae
- highly transmissible, especially in daycare and school settings
-
- esp. neonatal
other pathogens
- fungi and parasites are rare causes and mainly in the immunocompromised
chemical
- swimming pool chlorine
- acids or alkalis
- noxious smoke or gases
- dust
- other irritants
allergic
- hay fever sufferers often develop bilateral conjunctivitis
- in addition to exposure from allergens, symptoms will vary according to genetic makeup, with at least 34 genes identified to be associated with symptoms2)
mechanical
- blocked tear duct in neonates
conjunctivitis.1786153082.txt.gz · Last modified: 2026/08/08 01:38 by gary1