Have you ever seen small blue or red lines on your face or legs? 

They are called spider veins, sometimes referred to as thread veins. Spider veins are generally no threat to your health (even if you don’t like the way they look).

What Causes Spider Veins?

Unlike arteries, which carry blood from the heart to the rest of the body, veins carry blood back to the heart. Veins don’t have a heart-like pump of their own. Instead, they contain valves that keep blood from flowing backwards.

If these valves become damaged or weak, particularly in the legs, blood may begin to pool within the vein, causing a bulge that can become visible as small lines or webs. On the face, these marks may develop as the result of sun damage or blood vessels bursting due to excessive pressure.

How Do Spider Veins Differ from Varicose Veins?

Damaged or weak valves can also cause varicose veins. The difference? Varicose veins are larger and deeper within the leg than spider veins.

Because they’re so small and close to the surface of the skin, spider veins rarely cause pain. Varicose veins are more likely to cause problems such as achiness, itchiness or heaviness in the legs, and they may lead to circulation problems as well.

What Makes People Prone to Spider Veins?

Because the valves within veins tend to become weaker over time, spider veins may develop as someone ages. But there are other reasons why some people may be more likely to develop spider veins.

Some of these factors you can’t control, such as family history. Being a woman is another; not only is female skin more prone to their development but the extra weight of carrying a baby can put pressure on the legs, leading to spider veins that may or may not disappear after a woman gives birth.

For the same reason, being overweight is another reason spider veins may develop. So is either sitting or standing for long periods of time, since leg veins have to work harder when you remain in the same position for hours at a time. And hormonal birth control, which can weaken vein valves, may also play a role.

How Are Spider Veins Treated?

Some people have spider veins removed because they cause discomfort or for cosmetic reasons. Treatments range from wearing compression garments—such as support hose or even prescription stockings—to various laser-based procedures. Other treatments involve substances injected into the vein that stops blood flow, causing spider veins to fade with time.

Can Spider Veins Be Prevented?

If spider veins run in your family, you may want to start wearing compression stockings even if they haven’t appeared yet. (You should also avoid clothing that is too tight, which can restrict blood flow in the legs.) In addition, it’s a good idea to apply sunscreen every day year round, and wear a hat to avoid the kind of sun damage that may lead to spider veins appearing on your face.

Other prevention measures include:

• Staying at a healthy weight to reduce pressure on the veins and keep blood moving smoothly.
• Getting regular exercise, which includes the avoidance of sitting or standing for extended periods; move around every 30 minutes or so. Exercise can also help with weight maintenance.
• Eating a healthy diet full of fresh fruits and vegetables.
• Elevating your legs when sitting or lying down to help prevent blood from pooling. Make sure you’re not putting pressure on the backs of your legs. 
• Avoiding overuse of hot tubs and saunas, which can increase the risk of dilated leg veins.
• Avoiding crossed-leg positions, whether sitting in a chair or on the floor.
• Not wearing high-heeled shoes, which can put a strain on your legs.