Spider veins, a lesser form of varicose veins, are twisted purple or blue raised veins are most commonly found in the back of the knees, thighs and calves in women, but men and teenagers are also susceptible. These veins can be painful and unsightly, but are generally considered harmless and can be removed by a doctor with a laser or with sclerotherapy, which is a treatment involving a fluid injected into the vein that causes it to shrivel. Varicose veins can be prevented by regular exercise and wearing support hosiery.
Varicose veins are often hereditary. If one or both of a teenager's parents have varicose veins, then they are more susceptible to developing them.
The body's levels of female hormones estrogen and progesterone can cause varicose veins. Some teenagers find varicose veins developing during puberty when the fluctuation of these hormones start. Pregnancy also places extra strain on veins by adding extra blood to the circulatory system.
Maintaining a healthy body weight can help reduce the risk in teenagers for developing spider veins. Obesity at any age puts extra strain on the circulatory system; being more than 20 percent over your recommended weight can cause varicose veins. Valves within veins control the blood flowing in the right direction, and strain on the circulatory system causes these valves to break down and the blood returning to the heart pools in the varicose vein areas, stretching out the walls of the veins.
Smoking is another contributer to varicose veins. Smoking narrows arteries and veins, causing premature aging and increasing pressure within the veins, according to BMJ group.
Standing, especially on hard surfaces such as concrete, sitting or crossing your legs for a prolonged amount of time adds extra pressure to the veins, causing the valves to wear down their function. Teenagers can develop varicose veins simply from sitting for long periods of time in school.