Spider veins get their name from the spider web like pattern they form.
Spider veins are red, but larger ones look bluish-purplish. Normally, the tiny veins in the skin are invisible, but in some people they expand and show through the skin. Some causes could be long-term exposure to the sun, pregnancy or hormone treatment. They may also be inherited. Spider veins are more obvious after mid-life, when the skin becomes thinner and loses some of its collagen.