Spider veins (also called telangiectasias) are clusters of tiny blood vessels that develop close to the surface of the skin. They are often red, blue, or purple; and they have the appearance of a spiderweb. They are commonly found on the face and legs.
Spider veins and varicose veins are caused by structural abnormalities of blood vessels. Veins carry blood back to the heart from other parts of the body. They utilize a series of one-way valves to avoid backflow of blood.