hypertrychosis [hopefully that's spelled right] is what you're referring to. that's probably where the werewolf myth came from, another theory is people would live close to the woods, sometimes they would see a wolf from their window, when the person ran outside, it was gone, but they would see a person walking down the street, so rumours began. same way people were accused of witchcraft.
vampires comes from a few things, real people and real diseases. as with werewolves, a persons imagination can run wild. i wrote this before in other forums, but i'll paste it here:
vampires are based off people like Vlad Dracula and Elizabeth Bathory. there's even a disease many feel it was based off, porphyria, in which a person's body doesn't make a certain enzyme crucial to a healthy life. as such their skin burns easily in the sun, so they avoid the light. what many choose to do is ingest blood, and organs which deal with producing and cleaning blood in ones body, as a way to get these enzymes. this is what the legends come from, not real vampires.