What is the difference between hay fever and a cold?

Hay fever vs cold: From a practical perspective, the symptoms of both of these disorders are the same--runny nose and sneezing, perhaps also with itching, running eyes. The difference is that a cold will only last 3-4 days usually, while allergy symptoms tend to be chronic (eg., last all spring). So if your cold symtpoms don't quit after a week, you probably have allergies.

Allergy vs infection: Hay fever is another term for allergic rhinitis, which is characterized by seasonal increases in allergy symptoms (runny nose, sneeze, congestion) due to pollen levels (weed pollen in the fall, tree pollen in the spring). A "cold" is an infection caused by a virus. A cold will usually resolve after 7-10 days, while hay fever may last an entire season.