It seems like only a very few years ago, I woke up and saw one spider vein and thought, 'Oh, No!, I'm getting old!' 
Now after spotting a couple on the face and many others on my arms and legs, I just look at them and say, 'Oh, No!, I'm getting older!' 
So I wondered if any one else sort of wondered why they have them?!
I know they're fairly common and men as well as women get them, although, more women overall have them.
I don't think the cause is the same for any of us. I wore a face lotion all one summer, and didn't read the complete insert. (Yes, it was one that said it would help 'minimize' wrinkles.) 
When I suddenly realized as the tan faded and fall approached that I'd acquired several more spider veins on the face...yes, the insert said do not wear in the sun as it may cause spider veins. 
So the wrinkles are loooooking goooood-but the cheeks are a little rosier...
I wanted some help to explain the reason for some of these little and big veins and low and behold...
It's called http://4woman.gov
Hugs, Teri 