What are some reasons why your hair would fall out?

For the past week or two, I've noticed that my hair has been falling out a lot. Like everytime, I brush it there's like a least half a hand full that came out. And whenever I run my fingers through it, there's more hair.
What could be the reasons why...

my hair would fall out?

any dyes or perms can cause that

Straightening it
or really anthing bad you add to your hair

1) Stress
2) Hormones
3) Unhealthy diets
4) Not taking care of your hair especially if its colour treated, relaxed, permed etc
5) Hair Styling (too much heat, hair products e.g. gel can damage your hair)
6) Medication
7) Cancer treatments
8) Don't brush wet hair because it makes it weak and causes it to break

dying doesnt nessecarily take your hair out.
ACTUALLY, if you dye your hair darker, its healthy for it.
just dont go lighter.
youll be fine.
my aunt dyed her hair ever since she 12, shes 38 now, and still has ALL of her hair.
(:
MYTHS I SAY.
haha;

thyroid problems, weak hair, your hair might just be thinning or something, even if your young, could be stress or a bunch of different things.