What is a grass and weeds allergy that starts with h?

A grass and weeds allergy that starts with "H" is hay fever, also known as allergic rhinitis. It is an allergic reaction to pollen from grasses and weeds, leading to symptoms such as sneezing, runny or stuffy nose, and itchy eyes. Hay fever typically occurs during specific seasons when pollen counts are high, affecting many individuals. Managing symptoms often involves avoiding allergens and using antihistamines or other medications.