They seem to spontaneously appear. I just seem to notice it one day, and not having noticed it the day before. They don't know for sure it is a collagen issue, but that is there best "educated" guess. They do not go away. I still have the very first one from about 9 years ago. I doubt I'm the only one either, but of all the doctors I've seen, and about 12 different dermatologists alone have looked at it, none had answers and the tests didn't help at all. I even had two different biopsies and they showed nothing. If anyone can figure out how to post pictures on here from one's computer, I could show them to you.