Freeze until firm. Hay Fever Hay fever isn't usually caused by hay and doesn't result in a fever. An allergy to particles in the air that are inhaled causes hay fever. Many people don't have a reaction to these particles. For some people, the body releases chemicals that produce a stuffed-up, runny nose, itchy eyes and throat, sneezing and excess mucus in the nose and throat.
Hay fever can occur any season.
Some people may be sensitive to tree pollens in the early spring. Others may be sensitive to summer weeds such as ragweed. Ragweed pollen is the most common cause of hay fever in late August. If you think you have hay fever, your doctor can help determine the cause. Medications or shots may help relieve your symptoms.