Spider veins are also known as thread veins. The exact cause of spider veins is not proven, but heredity, local trauma, and hormonal levels are believed to be contributing factors. Spider veins become more numerous with age, and mostly occur in women.

Spider veins are formed by the dilation of the small veins under the surface of the skin, mostly on the legs. They look like red or purple sunbursts or web patterns. Spider veins are also referred to as telangiectasia or broken capillaries. They usually pose no health hazard but may produce a dull aching or burning in the legs after prolonged standing.

Varicose veins are swollen or enlarged blood vessels caused by a weakening in the vein's wall or valves. They are located somewhat deeper than spider veins, are sometimes raised, and often appear blue. Advanced cases of varicose veins can be harmful to a patient's health because they may be associated with the development of ulcers and phlebitis. In about a quarter of cases of patients with spider veins, larger varicose veins are also present and these varicose veins require treatment prior to treatment of the spider veins 

Sclerotherapy is still the best and safest treatment for spider veins. It causes minimal discomfort. A concentrated salt (saline) or specially developed chemical solution (we usually use a solution called aethoxysclerol) is injected with a very small needle into the spider vein. This destroys the inside of the vein so it closes up. It later collapses and becomes scar tissue that is eventually absorbed by the body.

Sclerotherapy sometimes requires multiple treatment sessions. Post-treatment therapy includes wearing support hose for two days to a weeks following treatment. Although sclerotherapy works for current spider veins, it does not prevent future ones from developing.