ELI5: What is measles and why does it make red spots on your skin?

Imagine your body is like a castle, and sometimes tiny invaders called viruses try to sneak in and make you sick. Measles is a disease caused by one of these tricky viruses.

Think of the measles virus as a tiny, sneaky gremlin that loves to jump from person to person, usually through coughs and sneezes. When the gremlin gets into your body, it's like it sets up a little headquarters.

Your body has brave knights (your immune system) that fight off invaders. But sometimes, the gremlin is too fast, and it starts copying itself like crazy. These new gremlins travel around your body, causing problems like fever, a runny nose, and a cough.

Now, about those red spots! The gremlins cause inflammation, which is like your knights getting really angry and causing a little bit of damage while fighting. The red spots are actually tiny blood vessels near the surface of your skin that have gotten inflamed because the gremlins are nearby. The inflammation makes the blood vessels leak a little, causing the red, bumpy rash that we call measles.

So, to recap:

• Measles is caused by a tiny gremlin (virus).
• The gremlin spreads through coughs and sneezes.
• It makes you sick with a fever, cough, and runny nose.
• The red spots are caused by your body fighting the gremlin near your skin, making your blood vessels angry.