Also-if you take steroids at all for your AS-they also thin the skin. I take steroids everyday in really small doses for autoimmune Addison's Disease, so it really shouldn't thin my skin, as it is just replacing cortisol that my body doesn't make anymore-but I'm sure it doesn't help, either.

Aging will also cause skin changes. I am 35, and I noticed my body has changed in other ways in the past year or so. My cycle is still regular-but it has changed its behavior and presentation if that makes any sense haha, and age and hormones really affect skin. I think I read that mid thirties is about when a woman's cycle starts to change a bit-heading to the big finally. It isn't full blown perimenopause or anything-but something to think about.