What Causes Itchy Bumps All Over The Legs?

i have lil bumps all over my legs and they itch. and my legs look blotchy. theres white blotches then my reg skin color. i look like i have a bunch of random white freckles all over my legs. it itches so bad i just want to rip my skin off. what is it? it is spreading. i have not been in the woods or near the woods. i live in fl and tan alot thats about the only time i will go outside. what could this be?