Conjunctivitis Dr Trisha Macnair Conjunctivitis is inflammation of the delicate surface membrane that normally forms a thin, transparent covering across the eye and folds back up inside the eyelid.

In this article

What causes it? What are the symptoms?

Who's affected? What's the treatment?

Conjunctivitis is caused by infection or irritants, including allergens.

In newborn babies, it's more often the result of a bacterial infection

The most common cause of infectious conjunctivitis, especially in older children, is a virus. In newborn babies, it's more often the result of a bacterial infection, picked up from the mother in the birth canal.

In most cases, such infections aren't serious and settle quickly. However, gonorrhoea, herpes and chlamydia can also be passed on during birth, and these may be more damaging.

Common irritants that cause conjunctivitis include household chemicals, grit and the plant allergens that cause hay fever.

Conjunctivitis causes redness of the conjunctiva (the white of the eye and inside the eyelids), usually of both eyes. The eyes may be sore, itchy, burning and sometimes extremely painful. Bright light can make the condition seem worse.

If the cause is a bacterial infection, the eye may discharge a white/yellow sticky pus. This can crust on the eyelashes and glue the eyelids together, especially after sleep.

If an allergen is causing the conjunctivitis, the eyes may be swollen, itchy and produce a thin, watery discharge.

All children are vulnerable, although the causes vary with age.

If you suspect conjunctivitis, your doctor will be able to confirm it.

Simply cleaning the eyes may be all that's needed to help the condition settle

With newborn babies, simply cleaning the eyes may be all that's needed to help the condition settle.

Viral conjunctivitis usually lasts a matter of days, and complications are extremely rare.

For most people, the infection clears up within a week without needing specific treatment. Antibiotics make very little difference, so nowadays they're less often recommended. Occasionally a more severe conjunctivitis can develop which involves the cornea (the area of the surface membrane that covers the iris and pupil). This type of conjunctivitis, for example caused by an infection with the Herpes virus in adults, may last several weeks and may require more intensive treatment with antibiotics and steroids, and careful follow-up by a specialist.

Allergic conjunctivitis is treated with anti-inflammatory eye drops. Gently bathing the eye and lashes with cooled boiled water may help.

So just to sum up, viral conjunctivitis usually lasts a matter of days and complications are extremely rare. Bacterial conjunctivitis can take several weeks to clear up. See your GP if you're at all worried about your child's eyes.

This article was last medically reviewed by Dr Rob Hicks in January 2008