Although the smallest visible veins on the legs are harmless from a medical point of view, they represent an annoying cosmetic problem and can be removed. These superficially located reddish or bluish vessels shine through the skin. Spider veins tend to appear on the ankles, lower legs and thighs. However, a medical examination of spider veins is recommended in order to rule out a pathological vein condition in the sense of varicose veins (varices).