What is Hay Fever?

You may be surprised to learn that it is very rarely related to hay, although the term was introduced when seasonal allergies affected farmers who worked in hay fields. The allergens, which trigger the symptoms we like to call hay fever, are caused primarily by pollen from trees, weeds, and grasses. So, is hay fever considered an allergy? Yes, but not necessarily to hay as you’d expect based on the name.

What Causes Hay Fever?

The list of what causes hay fever is long, and it’s common for people with one type of allergy to also react to other triggers. The main offender is the pollen released into the air by different types of plants and trees. When you inhale pollen, the cells in your body release histamine, which leads to common symptoms like sneezing. You can learn more about why pollen makes you sneeze here.

What Are Common Hay Fever Symptoms?

Symptoms of hay fever, which include itchy and watery eyes, sneezing, stuffiness, and an itchy, runny nose, don’t really differ from symptoms of indoor allergies.4 You may also experience an itchy roof of mouth or throat, swollen under-eye skin, and fatigue.5

As much as these symptoms may feel like an uncomfortable nuisance, they occur for a reason. Swelling, such as you might experience in your sinuses, is a mechanism the body uses to prevent more allergens from entering the body once it has detected an irritant. Sneezing is a mechanism your body uses to remove any irritants from your nose or throat that may have already found their way in.6

Common Symptoms

When Is Hay Fever Season?

Unsurprisingly, the answer to, “When does hay fever start?” or, “How long does hay fever last?” will depend on the weather and triggers where you live, since the pollen count in an early spring month like March is likely to be worse in Florida (where it’s warm and plants are blooming) rather than Minnesota (where the flora may very well be covered in a layer of frost or snow). That being said, it’s also based on precisely what triggers your sneezing, since hay fever symptoms generally crop up in spring, summer, and/or early fall when pollen from trees, weeds, and grasses are in full effect. Specifically, tree pollen tends to be at its worst in the spring, grass pollen is released during the end of spring and beginning of summer, and weed pollen steals the show in late autumn.⁷ Learn more about what allergens you can expect in which month in our Pollen-Month-By-Month guide.

The time of year isn’t the only factor in how bad your hay fever will be on a given day. The amount of pollen in the air will likely impact the severity of your symptoms.⁸ Pollen counts tend to be highest on warm, dry, and breezy days, especially in the morning; cool, rainy days tend to have the lowest pollen counts. Check out the ZYRTEC® ALLERGYCAST® app which helps predict how the pollen count may make you feel.

Common Culprits of Hay Fever