Hay fever is a seasonal allergy that is a ＿＿（46）＿＿ to high levels of pollen and fungal spores in the air. It generally occurs ＿＿（47）＿＿ February and May each year, when trees are releasing large amounts of pollen into the environment. Some common symptoms of hay fever ＿＿（48）＿＿ itchy eyes, a runny nose, and frequent ＿＿（49）＿＿ sneezing. Oddly enough, when a person gets hay fever, their immune system is actually overacting to a harmless substance. In an attempt to deal with the excess pollen, the body will ＿＿（50）＿＿ a chemical called histamine into the person’s nose, mouth, and eyes, which triggers the allergic reaction.