An unsightly pattern of bluish blood vessels that can have a spiderlike appearance and are visible in the skin of the legs. Spider veins are a mild form of varicose veins. They are common and medically insignificant, but some people seek treatment for cosmetic reasons. One type of treatment, known as sclerotherapy, involves injecting a saltwater solution into a visible vein. This scars the vein and prevents blood from flowing into it. In most cases, the treated vein loses color in 2 months or less. Some people develop a yellow-brown discoloration at t he treatment site that may not fade for several months.