What is it?

Conjunctivitis describes inflammation of the conjunctiva, the thin mucous membrane that covers the inner eyelid and sclera (white of the eye), and is commonly derived from three main sources: bacterial, viral and allergic.

 

Anatomy and physiology

 

The conjunctiva is a thin transparent vascular mucous membrane which invests the inner eyelid surface and anterior sclera. It’s vital in maintaining a suitable environment for the cornea, and providing a defence route against infection and trauma. Physiologically, dilatation of the conjunctival vessels results in both hyperemia and conjunctival oedema. The former causes excess blood accumulation, resulting in the typical ‘bloody red’ appearance, whilst the latter causes discharge.

 

The most common etiological pathogens are Streptococcus and Staphylococcus. Haemophilius influenza should also be considered in young children. Chalmydial and Gonoccoal infections may also be seen in sexually active individuals. 

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Viral Conjunctivitis

 

Diagnosis

 

Areas to explore when taking a history from an individual with suspected conjunctivitis may include:

• Character of discharge e.g. purulent, serous

• Pain?

• Itchiness?

• Photophobia?

• Changes in visual field?

• Unilateral or bilateral symptoms

• Eyes stuck together in the morning?

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Risk Factors to consider include:

• Sharing towels/pillow cases

• Recent upper respiratory tract infections (URTIs)

• Contact lens wearer

• History of autoimmune disease

• History of atopy

• Any close contacts who have conjunctivitis

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Bacterial Conjunctivitis with Pus

 

Examination findings include:

• Discharge from eyes

  • Bacterial – creamy, pus

  • Viral – watery

  • Chemosis

  • Tender pre-auricular lymphadenopathy (more common in viral than bacterial)

  • Papillae on inner eyelid (allergic conjunctivitis)

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Investigations to aid diagnosis may include taking swabs or conjunctival scrapes of the eye, however diagnosis is typically clinical and based on a thorough history and examination.

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Papilla seen in Allergic Conjunctivitis on the inner, upper eyelid

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Treatment

Conjunctivitis typically self-resolves within 1-2 weeks, provided good hygiene and lifestyle advice is practiced e.g. avoiding towel-sharing, regular hand washing and not rubbing eyes. Contact lens wearing should be avoided till the conjunctivitis has completely resolved.

 

Medical intervention may be used in more severe or persistent cases. Bacterial conjunctivitis can be treated with antibiotic eye-drops; chloramphenicol and fusidic acid are examples of commonly used antibiotics. Antihistamines or topical mast-cell stabilisers may be prescribed for those suffering from allergic conjunctivitis, particularly if patients have chronic seasonal symptoms.

 

If infants less than 1 month old present with symptoms, they should have an urgent ophthalmology review to rule out neonatal conjunctivitis.