The causes, symptoms and treatment of inflammation of the conjunctiva.
Medically reviewed by Dr Roger Henderson and based on a text by Per Lykke Gregersen, consultant
Conjunctivitis is a common condition that causes inflammation of the conjunctiva, the thin layer of tissue that covers the front of the eye. It is also sometimes referred to as red eye thanks to its inflamed nature.
Conjunctivitis usually affects both eyes and treatment depends on the cause, but it often clears up within a couple of weeks. We look at the causes and best treatments for this eye condition:
What is conjunctivitis?
Conjunctivitis is an eye condition caused by an infection or allergies, characterised by inflammation of the conjunctiva – the mucous membrane covering the white of the eyes and the inner side of the eyelids.
Symptoms commonly affect both eyes at the same time and include bloodshot eyes, a burning or gritty feeling, pus and sticky eyelashes, itching and watery eyes.
When should you visit a doctor?
Conjunctivitis can be uncomfortable and irritating, but is usually not serious and should clear up in a couple of weeks without treatment.
Conjunctivitis can be uncomfortable and irritating, but is usually clears up in a couple of weeks without treatment.
If symptoms persist or you wear contact lenses and develop conjunctivitis symptoms, make an appointment to see your doctor. While the condition is usually nothing to worry about, people who wear contact lenses can develop an infection of the cornea, which may require specialist treatment.
Conjunctivitis treatment tips
There are several things you can do to ease symptoms or prevent the further spread of infection:
✔️ Wash your hands regularly with warm soapy water to avoid spreading the infection.
✔️ Use clean cotton wool (one piece for each eye) and bathe your eyes with lukewarm salt water, gently rubbing your eyelashes to clean off crusts.
✔️ Use disposable tissues when you dry your eyes and dispose after use to limit contamination.
✔️ Wash pillows and face cloths in hot water and detergent.
✔️ Never share eye make-up or eye drops with another person.
If conjunctivitis doesn’t clear up on its own, you may require treatment. This depends on the type of conjunctivitis, so check the causes below, or visit your doctor.
What causes conjunctivitis?
There are five different kinds of conjunctivitis, each with their own cause, symptoms and treatment:
Bacterial conjunctivitis is an infection caused by bacteria, such as Staphylococci, Streptococci or Haemophilus. These organisms may come from the patient’s own skin, upper respiratory tract or caught from another person with conjunctivitis.
- Bacterial conjunctivitis symptoms
Bacterial conjunctivitis affects both eyes. The eyes will usually feel gritty and irritated with a sticky discharge. The eyelids may be stuck together, particularly in the mornings, and there may be discharge or crusting on the eyelashes.
- Bacterial conjunctivitis treatment
This type of conjunctivitis 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.
Evidence shows that while 64 per cent of bacterial conjunctivitis cases will clear on their own within five days, antibiotic eye medication does lead to increased success rates and earlier remission.
Viral conjunctivitis can be caused by adenovirus and is often associated with the common cold. This type of conjunctivitis can spread rapidly between people and may cause an epidemic. People often feel unwell and ‘under the weather’ when they have viral conjunctivitis.
⚠️ Viral conjunctivitis is a highly contagious condition. It’s important to ensure that a strict code of hygiene is adhered to including hand and face washing, and no sharing of face towels.
- Viral conjunctivitis symptoms
Viral conjunctivitis is characterised by red eyes and a watery discharge. The eyelids and even the conjunctiva on the white of the eye may swell, creating a glassy appearance.
The eyes are uncomfortable, with patients usually describing a sensation of ‘something in the eye’. There may also be the generalised symptoms of a cold, including tender lymph nodes (swollen glands) around the ear or the neck.
This type of conjunctivitis may also spread to the cornea (keratitis) to cause hazy vision. It can persist for several weeks.
- Viral conjunctivitis treatment
Viral conjunctivitis cannot be cured, but the symptoms can treated to improve comfort. A lubricant ointment, such as Carbomer can be used to make the eyes more comfortable. Cold compresses on the eyes and tablets, such as paracetamol and ibuprofen, can also help ease symptoms.
Close contact with other people, eg at school, is not recommended for the first one to two weeks to help prevent spread of the infection. This condition may persist for a prolonged time and in some instances corticosteroid drops have been advocated, although these should only be given under the strict supervision of a doctor.
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 sexually transmitted infection, chlamydia.
- Chlamydial conjunctivitis symptoms
Chlamydial conjunctivitis causes one or both eyes to be red with a sticky discharge and, sometimes, swollen eyelids.
- Chlamydial conjunctivitis treatment
Chlamydial conjunctivitis is treated with antibiotic tablets to ensure that infection is eliminated, including any possible infection of the genitourinary tract.
Because of the possible infection of other body sites, any sexually transmitted
infections should be identified and both the patient and their partners must be
Allergic conjunctivitis is common in people who have other types of allergic disease, such as hay fever, asthma and eczema. Allergic conjunctivitis is often caused by antigens like pollen, dust mites or cosmetics.
- Allergic conjunctivitis symptoms
Symptoms of allergic conjunctivitis include intense itching of the eyes, intermittent red eyes and stringy discharge.
These symptoms may occur at particular times of the year, such as spring and summer, when there is a lot of pollen in the air. Some people unfortunately can get allergic conjunctivitis all year round.
- Allergic conjunctivitis treatment
Allergic conjunctivitis can be treated using antihistamine or sodium cromoglicate drops to stop the body mounting an allergic response.
Lubricating/moisturising eye drops can also be used to soothe the surface of the eyes. The main treatment for allergic conjunctivitis should be identifying what is triggering the allergic response and removing it.
- Chemical or irritant conjunctivitis
Some people are sensitive 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.