Allergic conjunctivitis

Abstract

Acute allergic conjunctivitis is a sudden-onset reaction that occurs when one encounters a known allergen for that person, such as cat dander. An allergen is a substance that can potentially cause an allergic reaction.

In some people, the immune system recognises allergens as foreign or dangerous, and reacts by making antibodies to defend itself against the perceived threat. This will cause histamine to be released, and the eyes may become itchy, red and teary. Allergic conjunctivitis does not usually cause serious complications. A number of eye drop formulations are available over-the-counter (OTC), which may help relieve the symptoms of allergic conjunctivitis.