Some people believe that allergies can cause a fever, but that isn’t true!
Hay fever (also called allergic rhinitis) is a common allergy, and despite the name, it isn’t a reaction to hay and doesn’t cause a fever.
Hay fever symptoms include a runny or stuffy nose, and an itchy mouth, eyes or skin. Many people experience it seasonally because they are sensitive to airborne mold spores and pollens from grasses, trees and other plants. Others experience symptoms year-round, caused by environmental allergens like dust mites, pet dander and cockroaches.
If you’re experiencing a runny or stuffy nose and a fever, you may have a sinus infection. Sinus infections are caused by bacteria or viruses, not by allergies.