Spider veins are visible small veins within the skin. These are a form of varicose vein disease and could be the first sign of venous insufficiency. The size of spider veins may be thinner than a hair or nearly as wide as a spaghetti noodle. They can be of different colors and vary from pink, to red, to purple. They can be single and isolated, or occur in clusters that can look like a large bruise. Spider veins can occur anywhere but are most frequent on the thigh and calf of the lower extremities. They are permanent once they appear and tend to increase in number over time.