Allergic conjunctivitis, also known as allergic rhinoconjunctivitis or hay fever, is a common allergic reaction that occurs when the immune system reacts to allergens like pollen, dust mites, or pet dander. Symptoms of allergic conjunctivitis include redness of the eye, itching, watering, and swelling. There are several synonyms for allergic conjunctivitis, including seasonal allergic conjunctivitis, perennial allergic conjunctivitis, giant papillary conjunctivitis, and vernal keratoconjunctivitis. Each type of allergic conjunctivitis has slightly different symptoms and triggers, and treatment options vary depending on the severity of the condition. If you are experiencing symptoms of allergic conjunctivitis, speak to your doctor or an eye specialist for an accurate diagnosis and treatment plan.