What Are the Different Hay Fever Causes?
Hay fever is an allergic reaction that may occur seasonally or year-round. Hay fever symptoms in the spring and fall of the year may be caused by inhalation of allergens such as pollen or mold spores. Pet dander and dust mites sometimes trigger year-round hay fever symptoms. Contrary to its name, hay fever is not usually caused by exposure to hay, and its symptoms do not include a fever. Hay fever causes symptoms that may affect the eyes, ears, and nose of an affected person. Hay fever may result when a person inhales an airborne substance called an allergen. Allergens enter the body through the mouth, nose, throat, and lungs. They are not usually harmful, but once they are inside the body, the immune system may identify them as dangerous and produce antibodies to attack them. The next time a person inhales the same allergen, the immune system may recognize it and begin to produce a chemical called histamine to counteract the allergen.
