The conjunctiva is the deepest layer of of the eyelid and provides protection and lubrication of the eye by the production of mucus and tears. It prevents microbial entrance into the eye and plays a role in immune surveillance. It lines the inside of the eyelids and provides a covering to the sclera.
Conjunctivitis is the most common eye pathology in primary care. We can divide it into:
- Infective conjunctivitis - can be either bacterial or viral.
- Allergic conjunctivitis
Bacterial conjunctivitis is less common than viral. However, it is very contagious.
😷 Presentation
Worse in the morning with the eyes glued shut (hence the term glue eye).
Purulent discharge
🦠 Causative agents
- S. aureus
- S. pneumoniae
- H. influenzae
- Moraxella catarrhalis
- Chlamydia trachomatis
- Neisseria gonorrhoeae
It is more common and is also highly contagious.
😷 Presentation
Serous discharge (clear)
Recent URTI - dry cough, sore throat, blocked nose.
Preauricular lymphadenopathy
🦠 Causative agents
⭐️ Adenovirus - overall the most common cause.
Rhinovirus
HSV
VZV
😷 Presentation
Besides what we’ve mentioned specifically for bacterial and viral conjunctivitis:
- Red eyes
- Can be unilateral or bilateral.
- Itchy
- Gritty sensation
- Discharge - purulent or serous.
📝 Differential diagnosis
A painless red eye can be:
- Conjunctivitis
- Episcleritis
- Subconjunctival haemorrhage
A painful red eye can be due to:
- Scleritis
- Anterior uveitis
- Glaucoma
- Iritis
- Trauma
- Keratitis
- Corneal abrasion/ulceration
🧰 Management
As it is mostly viral, it is self-limiting within 1 - 2 weeks. NICE recommends isolation to prevent spread (for 2 weeks).
- Bacterial conjunctivitis - antibiotics are given.
- Chloramphenicol - given as drops every 2-3 hours.
- Fusidic acid - may be given to pregnant women instead.
- Contact lenses - patient should avoid them and also they need to be assessed for corneal staining with fluorescein.
- If it is a baby <1 month old they need urgent paediatric/ophthalmology review to assess for gonococcal infection. MC&S needs to be done and IV antibiotics need to be administered.
- Advise to not share towels and to not rub eyes too much. The eyes can be cleaned with sterilised water.
🚨 Complications
- Gonococcal infection - in neonates can lead to blindness and pneumonia as well as other complications.
It occurs with allergic rhinitis (hay fever) as a result of allergen exposure.
😷 It presents as:
- Bilateral conjunctivitis
- Bilateral chemosis (swelling)
- Itchy eye
- Eyelid swelling
- Cobblestoning on the inner eyelid.
🧰 We can manage it with:
- 🥇 Antihistamines - either topical or systemic.
- Cetirizine - an H1 antagonist.
- Olopatadine - bidaily is also used.
- Topical mast-cell stabilisers - prevents histamine release by mast cells.
- Sodium cromoglicate
- Nedocromil