Answer:
In my life I must bare my bloodline I must share.
When I am caught, I am thrown away. When I escape, you itch all day. What am I?
I run up and down the stairs without moving
You can see it everyday, but cannot touch it at will. What is it?
I widen my jaws when you poke two fingers in me. I especially like to devour papers
What do you purposefully put lots of in and on your body, but run away from when you encounter it outside?