Today’s Wonder of the Day was inspired by Fionn. Fionn Wonders, “Why does blood come out of your nose?” Thanks for WONDERing with us, Fionn!

When winter approaches, the air tends to get cold and dry. If you come down with a cold, you might find yourself constantly reaching for tissues as you blow your nose repeatedly. All that stress on your poor nose might lead to a common ailment known as a nosebleed.

Unlike a lot of medical jargon, nosebleed is one of those terms that simply and clearly describes what is going on: your nose is bleeding! Nosebleeds aren't pleasant. After all, who wants blood running out of their nose?

Nosebleeds are usually harmless. That doesn't mean you won't want to stop the bleeding as soon as possible, though.

Nosebleeds usually start in one nostril and occur in the front part of the nose. This is where tiny blood vessels sit very close to the surface. This makes them vulnerable to breaking and bleeding in certain circumstances.

So what can cause those tiny blood vessels to break and bleed? There are several common causes of nosebleeds. Although it's gross to think about, picking your nose can cause a nosebleed when your nails accidentally scratch the inside of your nose.

Other common causes include dry air, which leads to the inside of the nose becoming dry and cracked, and colds or allergies, which result in blowing your nose over and over again. Although less common, injuries to the nose and face can also cause nosebleeds.

If you get a nosebleed, what should you do? Should you call 911? Is a trip to the doctor necessary? Sometimes nosebleeds can escalate to the point where medical attention may be required. Most of the time, though, you can use a few simple first aid techniques to stop the bleeding yourself.

If you get a nosebleed, stay calm. Resist the urge to lie down. Instead, stand or sit up. Grab some tissues or a towel to catch the blood. Lean your head forward and firmly pinch the soft sides of your nose together until the bleeding stops.

When blood drips out of your nose, you may be tempted to tilt your head back to keep the blood from spilling down your chin. Tilting your head back, though, can cause blood to run down your throat, which can upset your stomach and make breathing more difficult.

Pinching your nose will help the blood to clot, bringing the flow to a stop. It can take several minutes, though, so it's important to be patient. If the flow of blood continues unchecked after 15-20 minutes, you will want to get help from an adult who can evaluate whether a trip to the doctor is necessary.

Nosebleeds usually don't occur all that often, although some people are more prone to them than others. If you have trouble with nosebleeds, there are several things you can do to try to prevent them. Keep things — including your fingers! — out of your nose. Use a humidifier at home in the winter to keep the air moist. You can also use a nasal spray, if a doctor recommends one.

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