Conjunctivitis (inflammation of the eye)

Reviewed by Dr Caroline McEwan, consultant ophthalmologist and Dr Whye Onn Ho, specialist registrar

What is conjunctivitis?

Inflammation is seen as reddish change in the periphery of the eye often accompanied by a pus-like discharge.

Conjunctivitis is an inflammation of the conjunctivae, which are the mucous membranes covering the white of the eyes and the inner side of the eyelids.

It usually affects both eyes at the same time although it may start in one eye and spread to the other after a day or two. It may be asymmetrical, affecting one eye more than the other.

There are many causes and the treatment will depend upon the cause.

Conjunctivitis is a very common eye condition. It is not serious but can be very uncomfortable and irritating.

What causes conjunctivitis?

There are five different kinds of conjunctivitis, each with its own cause.

Bacterial conjunctivitis

Bacterial conjunctivitis is an infection caused by bacteria such as staphylococci, streptococci or haemophilus. These organisms may come from the patient's own skin or upper respiratory tract or they may be caught from another person with conjunctivitis.

Viral conjunctivitis

Viral conjunctivitis is often associated with the common cold. This may be caused by a virus called 'adenovirus'. This type of conjunctivitis can spread rapidly between people and may cause an epidemic of conjunctivitis.

Chlamydial conjunctivitis

This type of conjunctivitis is caused by an organism called Chlamydia trachomatis. This organism may also affect other parts of the body and can cause the venereal disease chlamydia.

Allergic conjunctivitis

Allergic conjunctivitis is common in people who have other signs of allergic disease such as hay fever, asthma and eczema. The conjunctivitis is often caused by antigens like pollen, dust mites or cosmetics.

Reactive conjunctivitis - chemical or irritant conjunctivitis

Some people are very susceptible to chemicals in swimming pools or to smoke or fumes and this can cause an irritation of the conjunctiva with discomfort, redness and watering. In such cases these irritants should be avoided.

What are the symptoms of conjunctivitis?

Bacterial conjunctivitis

This is a condition that affects both eyelids. They usually feel gritty with a sticky discharge. Both eyes are red. The eyelids may be stuck together particularly in the mornings, and there may be discharge on the eyelashes.

Viral conjunctivitis

The eyes are red and there may be a watery discharge. The eyes are uncomfortable and there may also be symptoms of a cold. Sometimes there are tender lymph nodes around the ear or the neck. This type of conjunctivitis may also spread to affect the cornea (keratitis) and it may persist for several weeks.

Chlamydial conjunctivitis

Both eyes will be red with a sticky discharge. The cornea may also be involved in this condition.

Allergic conjunctivitis

Allergic conjunctivitis is usually associated with intense itching of the eyes. There may be a stringy discharge and the eyes are usually intermittently red. This may occur at particular times of the year, for instance during spring and summer when there is a lot of pollen in the air.

Conjunctivitis in young children

Small children may be susceptible to infective conjunctivitis and they may develop severe forms of the condition because of poor immune defences. This is particularly the case in babies and conjunctivitis in an infant aged less than one month old is a notifiable disease in the UK.

This type of conjunctivitis (ophthalmia neonatorum) may be due to an infection that has been contracted during the passage through the birth canal and may include gonococcal or chlamydial infection. Small babies may develop conjunctivitis from other types of infection but swabs should always be taken in order that appropriate treatment can be given.

Small babies often have poorly developed tear drainage passages (a condition known as nasolacrimal duct obstruction). These children are susceptible to watering eyes and they may intermittently become sticky, but this is usually not serious.

How is conjunctivitis treated?

Bacterial conjunctivitis

This is usually treated with broad spectrum antibiotic drops or ointment, (eg chloramphenicol or fusidic acid). The eyes should also be cleaned with cotton wool soaked in cooled boiled water to remove any crusts or stickiness. For bacterial conjunctivitis, research evidence shows that while 64 per cent of cases will clear on their own within five days, antibiotic eye medication does lead to increased cure rates and earlier remission.

Viral conjunctivitis

There is no effective treatment for viral conjunctivitis but the eyes may be made more comfortable by using a lubricant ointment such as Lacri-Lube. Chloramphenicol ointment will also help to prevent secondary bacterial infection.

As this is a highly contagious condition it is important to ensure that a strict code of hygiene is adhered to, such as hand and face washing and no sharing of face towels. This condition may go on for a prolonged time and in some instances corticosteroid drops have been advocated although these should only be given under the strict supervision of an eye specialist (ophthalmologist).

Chlamydia conjunctivitis

Treatment is with chlorotetracycline ointment and tetracycline tablets in order to ensure that infection elsewhere is controlled. Children cannot be treated with tetracycline and erythromycin is usually used for them. Because of the possible infection of other mucous membranes any associated venereal disease should be identified and both the patient and their partners must be treated.

Conjunctivitis in infants

This needs to be taken very seriously. Specimens are taken from the sticky discharge and such children must be seen by an ophthalmologist. Treatment is given depending on the underlying cause of the conjunctivitis.

Allergic conjunctivitis

This can be treated using topical antihistamine drops. Drops such as sodium cromoglicate (eg Opticrom eye drops) can be used to prevent the allergic response and they need to be used for many weeks in order to give any result.

Corticosteroid drops are occasionally used, but should only be used under the supervision of an ophthalmologist. The main treatment should be identifying what is triggering off the allergic response and removing this source of allergen.

How does the doctor make the diagnosis?

Conjunctivitis can usually be diagnosed and treated by your GP.

The doctor will usually diagnose the condition based on examination of your eyes and the history that you give.

Sometimes a swab has to be taken from the eye, especially if there is no improvement on standard treatment.

In some cases that are severe or do not respond to treatment, you may need to see an eye specialist (ophthalmologist).

What should I pay particular attention to?

If there is any worsening of the symptoms despite treatment or if the vision deteriorates, then a further consultation with your doctor should be requested even if treatment is being carried out.

What can be done to avoid conjunctivitis?

Good hygiene of hands and face is important. There should be no sharing of face towels, especially if someone has conjunctivitis.

Conjunctivitis can spread from one eye to the other, especially when you rub your eyes. Pus and crust should be removed by bathing the eye with lukewarm salt water which can also lessen the symptoms.

Use disposable tissues when you dry the eyes and throw them away after use. This will limit the contamination. Dispose of any antibiotic eye drops after the treatment is over.

People who suffer from conjunctivitis should have a special towel that only they use.

How does conjunctivitis usually progress?

Even if left untreated, most forms of conjunctivitis will gradually get better on their own in a few weeks.

With appropriate treatment the eyes are usually more comfortable within a few days, although cases of adenoviral infection may cause problems for some weeks.


Sheikh A, Hurwitz B, Cave J. Antibiotics for acute bacterial conjunctivitis. Cochrane Library. Issue 3, 1999.

Based on a text by Per Lykke Gregersen, consultant

Last updated 30.09.2008