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Viral conjunctivitis is a highly contagious acute conjunctival infection usually caused by adenovirus. Symptoms include irritation, photophobia, and watery discharge. Diagnosis is clinical; sometimes viral cultures or immunodiagnostic testing is indicated. Infection is self-limited, but severe cases sometimes require topical corticosteroids.
Etiology
Conjunctivitis may accompany the common cold and other systemic viral infections (especially measles, but also chickenpox, rubella, and mumps). Localized viral conjunctivitis without systemic manifestations usually results from adenoviruses and sometimes enteroviruses.
Epidemic keratoconjunctivitis usually results from adenovirus serotypes Ad 5, 8, 11, 13, 19, and 37 and tends to cause severe conjunctivitis. Pharyngoconjunctival fever usually results from serotypes Ad 3, 4, and 7. Outbreaks of acute hemorrhagic conjunctivitis, a rare conjunctivitis associated with infection by enterovirus type 70, have occurred in Africa and Asia.
Symptoms and Signs
After an incubation period of about 5 to 12 days, conjunctival hyperemia, watery discharge, and ocular irritation usually begin in one eye and spread rapidly to the other. Follicles may be present on the palpebral conjunctiva. A preauricular lymph node is often enlarged and painful. Many patients have had contact with someone with conjunctivitis, a recent URI, or both.
In severe adenoviral conjunctivitis, patients may have photophobia and foreign body sensation due to corneal involvement. Chemosis may be present. Pseudomembranes of fibrin and inflammatory cells on the tarsal conjunctiva, focal corneal inflammation, or both may blur vision. Even after conjunctivitis has resolved, residual corneal subepithelial opacities (multiple, coin-shaped, 0.5 to 1.0 mm in diameter) may be visible with a slit lamp for up to 2 yr. Corneal opacities occasionally result in decreased vision and significant halos and starbursts.
Diagnosis
Diagnosis of conjunctivitis and differentiation between bacterial, viral, and noninfectious conjunctivitis are usually clinical; special tissue cultures are necessary for growth of the virus but are rarely indicated. PCR and other rapid, office-based immunodiagnostic tests can be useful especially when the inflammation is severe and other diagnoses (eg, orbital cellulitis) must be ruled out. Features that may help differentiate between viral and bacterial conjunctivitis can include purulence of ocular discharge, presence of preauricular lymphadenopathy, and, in epidemic keratoconjunctivitis, chemosis. Patients with photophobia are stained with fluorescein and examined with a slit lamp. Epidemic keratoconjunctivitis may cause punctate corneal staining. Secondary bacterial infection of viral conjunctivitis is very rare. However, if any signs suggest bacterial conjunctivitis (eg, purulent discharge), cultures or other studies may be useful.
Treatment
Viral conjunctivitis is highly contagious, and transmission precautions must be followed as described previously (see Conjunctival and Scleral Disorders: Overview of Conjunctivitis). Children should generally be kept out of school until resolution.
Viral conjunctivitis is self-limiting, lasting 1 wk in mild cases to up to 3 wk in severe cases. It requires only cool compresses for symptomatic relief. However, patients who have severe photophobia or whose vision is affected may benefit from topical corticosteroids (eg, 1% prednisolone acetate qid). Corticosteroids, if prescribed, are usually prescribed by an ophthalmologist. Herpes simplex keratitis (see Corneal Disorders: Herpes Simplex Keratitis) must be ruled out first (by fluorescein staining and slit-lamp examination) because corticosteroids can exacerbate it.
Key Points
Last full review/revision October 2012 by Melvin I. Roat, MD, FACS
Content last modified October 2012
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