Welcome back, to SciShow Kids! coughing Don’t worry—I’m not sick.

I’m just having a little problem that I have in the springtime. My allergies are acting up!

Allergies aren’t something that you can catch from another person. That’s because, unlike colds or the flu, allergies aren’t caused by germs! But do you know what does cause an allergy?

Your very own body! An allergy happens when part of your body kind of … makes a mistake. And the part that’s confused is called your immune system.

Now, your immune system is actually made up of lots of different body parts. And all of these parts work together to do one important thing — to fight off the germs that can make you sick. This means that your body’s immune system is always working, even if you don’t notice it.

That’s because, although you don’t see them, there are lots of bacteria and viruses and other things that can you make you sick, all around you! They’re on the things you touch at home and at school, and they’re even floating in the air. But they don’t make you sick most of the time, because your immune system is on the job!

Now, if a germ should happen to get into your body, special parts of your immune system go on the attack. For example, in your blood, you have special white blood cells that do their best to surround and destroy as many of these dangerous invaders as they can. But this is only one part of the battle!

Other parts of your immune system are fighting back, too! Your body starts making lots of extra mucus or ‘snot’. This extra mucus runs out of your nose and down the back of your throat, flushing germs out of your body.

Meanwhile, you also start coughing and sneezing! When you cough or sneeze, that’s your immune system trying to blow germs right out of your body! So, your immune system is really amazing...but it’s not always perfect.

Now, an allergy is when your immune system makes a mistake! When this happens, your immune system tries to protect your body from something that’s not a dangerous germ -- instead, it gets triggered by something like dust, or your friend’s cat, or pollen from plants and flowers. We call these things allergens.

For example, pollen can be an allergen. It’s a little yellow powder that’s made by flowers and other plants. And there’s usually lots of pollen in the air in the spring.

Pollen’s not a germ, so it can’t make you sick that way the things that cause colds or the flu can. But in many people, pollen can cause an allergy. So, when pollen gets into your nose or your eyes, your immune system thinks it’s going to make you sick, so it goes on the attack.

It makes the inside of your nose swell up, making it feel itchy and stuffy. Or it can make you sneeze a lot, and to try and force that pollen out of your nose. It can also cause you to make a lot of mucus, or ‘snot’, to wash the pollen away.

This can make your nose really runny and drippy. And it can make your eyes itchy and watery and red, as your immune system tries to wash the pollen out. All of these things together can make you feel like you’re sick.

So most people who have allergies do their best to avoid allergens, or take medicines that help take care of the sneezing and runny noses. So, if you’re feeling healthy today—remember, it’s because your immune system’s working. But if you’re like me, and find yourself sneezing in the springtime...then it just might be that your immune system is a little confused C’mon, Squeaks...it looks like I’m almost out of tissues, so I’d better go grab some more!

Thanks for joining me at SciShow Kids! Do you have a question about how your body works? Find a grownup and ask them to help you leave a comment below, or ask them to help you send an email to kids@thescishow.com!