What are implications of thin blue/purple veins below skin all over legs, esp. mid portion above & below knees. can't be felt. late 50's. what's up?

Reticular veins: These are superficial veins which can run in family and may be associated with varicose veins.These can be treated cosmetically with sclerotherapy-injections of fda approved agents to cause dissolving of vessels.

Nothing special.: Everyone has veins; yours are just close enough to the surface to be visible. They are of no significance medically, but if they are cosmetically unacceptable to you, a dermatologist can decrease their visibility with something called sclerotherapy. Your insurance won't cover that, however.