These are usually finely-branched small veins that extend in a net or a fan shape across the epidermis and can form larger clusters. They appear as bright red vascular trees, dark blue small veins or red blotches. Although they are of little medical importance, they represent a significant cosmetic problem to a lot of people.
This is also due to a weakness of the connective tissue. Predilection sites are the outside of the thigh, inside of the lower leg and the hollow of the knee. Spider veins can be a first indication of a disease of the subjacent venous system and are frequently associated with varicose veins. Women are most commonly affected by them.