Allergic conjunctivitis

What is conjunctivitis?

The surface membrane of your eye is known as the conjunctiva. It forms a thin transparent layer over the white of your eye and under your eyelids.

Conjunctivitis means inflammation of the conjunctiva. It has several causes:

An allergy - allergic conjunctivitis.
An infection (bacteria or viruses) -infective conjunctivitis.

What are the symptoms of allergic conjunctivitis?

Allergic conjunctivitis usually affects both eyes. Symptoms may include:

Red, itchy, watery eyes
Sore eyes
Swollen eyelids
Blurry vision (due to the excessive tears)

You may get hay fever symptoms such as sneezing or a runny nose. Like hay fever, this condition can continue for some time (months).

What causes it?

Allergic diseases happen when the immune system reacts to harmless substances like dust, grass or pollen. It is more common in those with a history of allergies or those who have a family history of allergies. Allergy tests are not helpful. The seasonal type of allergic conjunctivitis will vary with the time of year and weather conditions. Those with more general allergies (e.g. dust mites, animals) may have symptoms throughout the year.

What are the treatment options for allergic conjunctivitis?

Avoid rubbing your eyes – it will make the symptoms worse.
Cold compress – this may help reduce eyelid swelling.
Lubricant eye drops or ointment – these may help reduce discomfort but will not stop the allergy process.
Anti-allergy eye drops – see table below. Most anti-allergy drops are available over the counter at a chemist. Anti-allergy drops need to be used every day and may take up to two weeks to work. Some people need drops for only a few weeks in the summer, some throughout spring and summer, and others need them all year round.
Antihistamine tablets – see table below. Provided you have no medical reason which prevents you from using antihistamine tablets, these can be taken every day. They are available over the counter at a chemist. Always read the patient information leaflet provided by the manufacturer before taking any medication. Speak to a pharmacist or GP for further advice if you are uncertain.
Steroid eye drops are used in severe cases - If all the above treatments are being used and there are still symptoms of allergic conjunctivitis, ask your GP to request an appointment with your local ophthalmology service. Steroid eye drops require a prescription, if they are needed.

Advice for contact lens wearers

Contact lenses should not be worn until symptoms have settled.

When to seek advice

If you develop persistent blurred vision, noticeable eye pain, or sensitivity to light, you should contact Moorfields for advice or go to your local A&E or urgent eye care department.