Varicose veins are enlarged veins, while spider veins are a smaller version of the same condition, though their appearance is different. Women are about twice as likely to develop this circulatory condition than men.

Though unsightly, varicose and spider veins don’t always require medical attention. When they do, sclerotherapy, injecting a solution into the vein to force blood to reroute to healthier veins, is a common treatment. In the most serious cases, surgery may be required.

These veins can cause dull discomfort that may get worse as you age, but severe pain is uncommon. Symptoms of discomfort may include:

• Swelling in your feet and legs
• Fatigued leg muscles and night cramps
• An itchy or burning sensation on the skin of your legs and ankles

Appearance and Location

Varicose veins have characteristics that you can see through your skin, such as:

• They’re red or blue in color.
• They have the appearance of cords running just under your skin that look twisted and bulging.

These veins pop up on various parts of your body, usually in the lower half, including:

• The backs of your calves
• The inside of your legs
• Anywhere from your groin to the ankle
• In your vagina or around your anus, during pregnancy

Spider veins look similar to varicose veins, but there are differences:

• They are smaller.
• They are often red, but sometimes blue, in color.
• They are closer to your skin’s surface.
• They look like a spiderweb, with short, jagged lines.
• They cover either a very small or very large area of skin.

When checking your body for spider veins, you can often find them on your legs and face.

Causes

Your veins are part of your circulatory system. As blood returns to your heart, healthy, strong veins act as one-way valves to prevent the blood from flowing backward.

When veins weaken, some of the blood can leak backward, collect there, and then become congested or clogged. This causes the veins to become abnormally large, resulting in either varicose veins or spider veins.

Science has yet to uncover exactly what causes the one-way valves to weaken, but several factors make you more likely to develop them, including:

• Heredity, or being born with weak vein valves
• Hormonal changes during puberty, pregnancy, and menopause (when your period has stopped for 12 months), as well as from taking hormones such as estrogen and progesterone, or birth control pills
• Pregnancy, which causes enlarged veins due to a significant increase in blood volume
• An enlarged uterus during pregnancy, which puts more pressure on the veins (with improvement seen after delivery)

Other factors that weaken vein valves and contribute to the appearance of varicose and spider veins include:

• Aging
• Obesity
• Leg injury
• Prolonged standing—commonly work-related for nurses, teachers, and food service workers

Prevention

You can try to prevent varicose and spider veins by taking the following steps:

• Exercise regularly to improve your leg strength, circulation, and vein strength.
• Control your weight to avoid placing too much pressure on your legs.
• Do not cross your legs when sitting and try to elevate your legs when resting.
• Wear compression stockings (special, snug-fitting socks to improve circulation).
• Do not stand for long periods of time.