Why does my mom have veins all over her legs and thighs?

V. veins: This may represent varicose veins. If they do cause pain they probably do not need to be treated.

Venous insufficeincy: Visible veins on the legs are the result of venous insufficiency. The insufficiency may be in skin [resulting tiny spider veins], or below the surface of the skin [ causing tiny and varicose veins] or in deep veins. It is best to have this evaluated by a vein specialist, often with aid of an ultrasound to see how best to treat. Now treatments are simpler and more effective than ever.