What is the relationship between hay fever and hay?

An old connection: Many years ago, before modern allergies were even diagnosed, physicians and scientists realized that exposure to hay caused typical allergy symptoms for some people. Hay is usually timothy grass, or another type of grass, and these people simply had allergies. The connection remains, and the term given to these symptoms were hay fever.

Hay Fever: There is none! the term is a foolish paradox since it describes allergic reactions but has nothing to do with hay and no relation to a fever (infection).

Good question: Hay is grass; grass is an airborne pollinator, and produces heavy amounts of it in late spring in the upper latitudes of the US. Fever is an urban myth; fever would mean runny nose is from an infection, NOT allergies.