Today’s Wonder of the Day was inspired by Nathan. Nathan Wonders, “Why do you have to put a epi pen in the thigh?” Thanks for WONDERing with us, Nathan!

Ahhhh…choooo! That's the sound that many people hear when allergy season rolls around. When flowers begin to bloom and pollen fills the air, seasonal allergies can flare up, causing eyes to water, noses to run, and heads to ache.

Many people also have allergies to things that can cause a reaction any time they come into contact with them. Do you have any friends who are allergic to cats? How about peanuts?

While some allergies can be a nuisance because they cause sneezing or itchy eyes, other allergies — especially food allergies — can be life threatening. For example, exposure to even a bit of peanut oil can cause anaphylaxis in someone with a severe peanut allergy.

Anaphylaxis is a severe allergic reaction in which the body releases a bunch of chemicals when it senses an allergen. These chemicals cause a variety of reactions throughout the body, including lowering blood pressure and constricting airways, both of which can be deadly if not treated quickly.

Most people with severe allergies of the type that can be deadly carry an important tool with them in case of an emergency. Known as an epinephrine auto-injector, these lifesaving tools go by several brand names, including EpiPen®, Auvi-Q®, and Adrenaclick®.

Although many people refer to any epinephrine auto-injector as an EpiPen, these tools don't actually look like pens you write with. Instead, they sort of resemble a long glue stick.

Different versions of epinephrine auto-injectors work in slightly different ways, but the basic premise is the same. After removing safety caps, the auto-injector can be pressed into a person's thigh muscle to automatically inject medicine in the body.

The medicine in an epinephrine auto-injector is the hormone epinephrine, which is also known as adrenaline. Epinephrine works quickly to reverse the effects of anaphylaxis.

When injected, epinephrine causes the body's blood vessels to constrict. This raises blood pressure. At the same time, it relaxes the airways to make it easier to breathe. Epinephrine also increases heart rate, which helps to improve blood flow.

In an emergency, every second counts. In the case of anaphylaxis, an epinephrine auto-injector should be used as quickly as possible. Always remember to follow the instructions printed on the package and call 9-1-1 to get professional medical treatment as soon as possible.

Wonder What's Next?

Tomorrow’s Wonder of the Day might seem a bit contradictory!