What is conjunctivitis?

Conjunctivitis is the medical term used to describe inflammation of the eye. It is a very common condition, which usually affects both eyes at the same time, although it can start in one and spread to the other within a day or two. It is not a serious condition, although it can be very uncomfortable and unpleasant.

The part of the eye which becomes inflamed is the conjunctiva, which are the mucous membranes covering the white of the eyes and the inner side of the eyelids.

What causes it?

There are three distinct types of conjunctivitis and treatment will usually depend on the cause. The three types are

Infective conjunctivitis, which is caused by bacteria, viruses or chlamydia.

Allergic conjunctivitis is caused by a reaction to allergens in the air, in cosmetics, or in dust mites.

Reactive conjunctivitis is caused by an allergic reaction to irritants as chemicals in swimming pools, cigarette smoke etc.

Bacterial conjunctivitis


Bacterial conjunctivitis is caused by bacteria such as staphylococci, streptococci or haemophilus which may be present on the person’s own skin or in the upper respiratory tract, or may be caught from another sufferer of conjunctivitis.


This condition affects both eyes, which feel gritty and have a sticky discharge in them. The eyes are also very red and the discharge may cause them to be stuck together, particularly in the mornings.


The vast majority of cases of bacterial conjunctivitis will clear up of their own accord within five days. The highest standards of hygiene should be applied in an effort to clear the infection and the eyes should be washed a number of times a day with cotton wool which has been soaked in cooled, boiled water.

If the infection does not clear up within five days, antibiotic eye medication (usually in the form of eye drops or ointment) may be required.

Viral Conjunctivitis:


This is usually associated with the common cold and can spread rapidly between people, especially in damp and wet weather.


The eyes are red and there may be a watery discharge. They will feel very uncomfortable and there will usually be other symptoms of the common cold present. The lymph nodes around the ears and neck may also become swollen and tender. Viral conjunctivitis can affect the cornea, giving rise to a condition known as Keratitis, and it can persist for several weeks.


This is a highly contagious condition and great care should be taken to avoid sharing towels or face flannels with someone who is infected. A strict code of hygiene should be adhered to at all times, with regular washing of the face and hands.

There is no effective treatment for viral conjunctivitis at the moment, although the use of steroid drops is sometimes advocated for those who are suffering from the condition for a prolonged period. These drops should only be used if prescribed by a doctor as the inappropriate use of steroid drops in the eye may cause serious problems.

Chlamydial conjunctivitis:


This is caused by an organism known as chlamydia trachomatis which can also affect other parts of the body and is responsible for the sexually transmitted disease (STD) called chlamydia.


This is sometimes confused with bacterial conjunctivitis as the symptoms are somewhat the same – both eyes are red with a sticky discharge. However, the cornea may become involved in this condition, unlike in the case of the bacterial form.


Medical intervention must be sought in all cases of chlamydial conjunctivitis and a specific type of ointment is used to treat the condition. Any sexually transmitted disease (STD) present must be treated, and the patient’s sexual partner will also have to be treated.

Allergic/Reactive conjunctivitis:


The first type of conjunctivitis (allergic) is common among people who suffer from other types of allergic disease such as hay fever, asthma and eczema. It is often caused by pollen, dust mites and cosmetics. The second type (reactive) usually occurs as a result of reaction to chemicals or other irritants, such as chlorine in swimming pools or cigarette smoke.


In both cases, the eyes will be intensely itchy, and there may be a stringy, watery discharge. The eyes will be intermittently red, and may feel very uncomfortable.


Anti-histamine drops are usually given, although steroid drops may occasionally be used. These must only be administered under the strict supervision of your GP or ophthalmologist.

However, the most effective method of treatment is to identify the particular type of allergen or irritant which is causing the infection so that you can avoid it in the future.

How will I know which type of conjunctivitis I have?

As the symptoms of conjunctivitis are generally the same, regardless of the cause, it may not be easy to decide which type of conjunctivitis you are suffering from. Your doctor will take a complete medical history and organize any tests that are required to confirm the cause.

What can be done to avoid conjunctivitis?

Good hygiene of the hands and face is important in the prevention of conjunctivitis. Sharing of face towels or flannels is not a good idea, particularly if one member of the household is infected, or prone to infection.

Infection can spread from one eye to the other by rubbing them. Use disposable paper handkerchiefs to wipe the eyes and always make sure to dispose of them properly after use.

Infected eyes should be washed with a warm solution of salt water and cotton wool, and remember to wipe the eyes from the bridge of the nose to the outer corner of the eye, and not the other way around.

Always dispose of any antibiotic eye drops, which are left over after the infection has cleared up.