Prominent or visible leg veins are very common and may be unsightly. Their exact cause is unknown, although genetics, childbearing, and long periods of standing are thought to play a role in their formation. Most spider veins are treated with sclerotherapy, although some may be treated with a laser.

Sclerotherapy involves injecting a sclerosing solution, or medicine, into small vessels, causing the vessels to close and slowly fade away. The veins start to fade within one week, continuing over a period of four to six weeks.

A laser may be used to treat some of the smaller veins on the legs. This may result in darkening around the treated vein similar to a bruise, which may last for several months.

More than one treatment is usually necessary for optimal effects. Most patients can expect a 50 percent to 80 percent improvement with a series of treatments.