ok, so I sometimes get this red pinprick looking rash on my upper arms, and my legs. it just comes out of nowwhere. I dont know if I am allergic to something or what. But my skin will look perfect, then all of a sudden it gets this rash all over like my legs and stuff. sometimes it's even like a big redish, purplish bruise with red pinpricks. Ive tried all sorts of treatments.
But just at am at a loss to what this is. I once was diagnosed with keratosis pilaris. but that was several years ago and I dont have the bumps for that, just red dots that come and go. So I dont think that is what I have. B/c the red dots are only there part of the time.
So any help would be greatly appreciated. I am so confused!
red pinprick rash that comes and goes? PLEASE HELP! 
