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What is allergic conjunctivitis?
Allergic conjunctivitis is an allergic reaction on the surface of the eyes. It is a very common condition that occurs when your eyes come in contact with allergy-causing substances (allergens). Pollen and smoke are examples of allergens.
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How does it occur?
The allergens may be in the air, such as dust, fine animal hair, smoke or plant pollen. When your eyes are repeatedly exposed to allergens, the body reacts and produces antibodies. When allergens in the air contact the antibodies in the eye, an allergic reaction begins. The eye releases chemicals, including histamine. These chemicals cause the symptoms of allergic conjunctivitis.
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What are the symptoms?
The eyes are itchy, watery and red. Sometimes the eyes may be swollen. Both eyes are affected unless just one eye came into contact with the allergen, as might happen with some drug allergies.
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How is it treated?
The first choice for treatment is to avoid the cause of allergy. Some people need to take antihistamine tablets, especially if they have other allergy symptoms. If you have only eye symptoms, eye drops may be the only medication required. These eye drops have anti-inflammatory, decongestant and anti-histamine properties. In the acute phase however, steroid drops may be needed for short periods of time, under medical supervision. If exposure to an allergen is anticipated, mast cell stabilizing drops like sodium cromoglycate orketotifen can help in prevention.
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How long do the effects last?
The symptoms of allergic conjunctivitis will last as long as the allergen is around, whether it is a pollen or cat dander in a carpet. People who had allergic reactions as a child and have continued to have them as an adult, will probably have them the rest of their life. However, anybody may develop an allergy, including allergic conjunctivitis, at any time in their life. Occasionally an eye infection (bacterial conjunctivitis) develops in addition to the allergic conjunctivitis. This may happen because bacteria get into the eyes when they are scratched or rubbed.
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Can allergic conjunctivitis be prevented?
Often there is no way to prevent allergic conjunctivitis. The symptoms may be lessened by limiting exposure to allergens. For example, avoid going outside when pollen counts are high or when the wind is blowing allergens through the air. Use air conditioning, if possible, rather than opening windows. Avoid using fans in dirty and closed spaces.
