Author: Dr Julie Fraser, Adelaide, Australia. Chief Editor: Dr Amanda Oakley, Dermatologist, Hamilton, New Zealand, December 2015.
Conjunctivitis is inflammation of the conjunctiva of the eye.
The conjunctiva is the semi-transparent membrane that covers the white part of the eye (the sclera) and lines the inside of the eyelids.
When the conjunctiva is inflamed, the white of the eye appears red. Conjunctivitis is the most likely diagnosis when a patient has a red eye and discharge.
Conjunctivitis caused by viral infection is sometimes called "pink eye", although this term is sometimes used for all forms of conjunctivitis. Viral conjunctivitis is highly contagious.
Viral conjunctivitis may be due to systemic or localised infection.
Viral conjunctivitis is typically caused by a systemic infection by adenovirus, and is associated with respiratory tract symptoms. It can also be due to local infection by herpes simplex, herpes varicella zoster virus (cause of chickenpox and shingles), picornavirus (enterovirus 70, coxsackie A 24), poxvirus (molluscum contagiosum) and human immunodeficiency virus.
Conjunctivitis is a diagnosis of exclusion. All forms of conjunctivitis are characterised by:
The following "red flags" point to other more serious diagnoses, such as keratitis (inflammation of the cornea), iritis, or angle closure glaucoma:
Pointers to a systemic viral cause of conjunctivitis include:
Epidemic keratoconjunctivitis (EKC) is a fulminant form of viral conjunctivitis and keratitis. Features include:
These more serious infections may threaten vision.
Herpes simplex infection (HSV) should be suspected in young children with follicular conjunctivitis. Herpes simplex infection can also cause keratitis, blepharitis, and iritis. It is associated with enlarged and tender preauricular lymph node. The presentation of other viral forms of conjunctivitis depends on the specific virus.
Most forms of conjunctivitis are self-limiting but in certain cases, severe complications may occur. Pain, loss of vision or photophobia require immediate referral to an ophthalmologist.
Complications from viral conjunctivitis include:
Viral conjunctivitis is a self-limited process. The clinical course of the systemic form of viral conjunctivitis parallels that of the common cold. Symptoms often worsen for 3–5 days, with gradual resolution over 1–2 weeks.
Symptomatic treatments include:
Severe cases may require hospitalisation for systemic and topical treatments.
Patients should be educated about hygiene measures to reduce the spread of the infection.
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