What Are Spider Veins?

Spider veins are small, visible blood vessels that appear close to the surface of the skin. They are usually red, blue, or purple and often form branching, web-like patterns on the legs. Spider veins are extremely common and are usually not dangerous, but they can be a source of frustration for people who are uncomfortable with their appearance.

For some people, spider veins are simply a cosmetic concern. For others, they may occur alongside symptoms such as aching, heaviness, swelling, or discomfort in the legs. In some cases, spider veins can also be associated with underlying problems with the veins that require evaluation.

Spider veins are different from varicose veins. Varicose veins are larger, raised, and often twisted or bulging, while spider veins are smaller and typically lie close to the surface of the skin.

What Causes Spider Veins?

Spider veins develop when small blood vessels near the surface of the skin become enlarged and more visible. Several factors can contribute to their development, including genetics, age, hormonal changes, pregnancy, prolonged sitting or standing, and increased pressure within the veins.

One important factor is venous reflux, which occurs when the one-way valves inside the veins do not work properly. These valves normally help keep blood moving from the legs toward the heart. When they become weak, blood can flow backward and increase pressure within the veins.

This increased pressure can contribute to the development of visible veins, including spider veins and varicose veins.

Not every spider vein is caused by venous reflux. Some develop independently and are primarily a cosmetic concern. A vein evaluation can help determine whether there is an underlying problem contributing to their appearance.

What Do Spider Veins Look Like?

Spider veins are typically much smaller than varicose veins and are usually flat against the skin rather than raised.

They may appear as individual lines, branching patterns, or clusters that resemble a spider web. They are most commonly found on the thighs, calves, ankles, and around the knees, although they can develop almost anywhere on the legs.

Spider veins can range in color from bright red to blue or purple. Over time, they may become more noticeable or increase in number.

Although spider veins themselves are usually not painful, some people with spider veins also have symptoms caused by underlying venous disease.

Are Spider Veins Dangerous?

In most cases, spider veins are not dangerous. They are very common and are often primarily a cosmetic concern.

However, their presence can sometimes indicate that the veins deeper in the leg are not functioning normally. When venous reflux is present, increased pressure within the veins can contribute to the development of spider veins as well as other symptoms.

If you have spider veins along with persistent aching, leg heaviness, swelling, itching, cramping, or other symptoms, it may be worth having your veins evaluated.

A sudden change in a leg, including significant swelling, pain, redness, or warmth, should be evaluated promptly because these symptoms can have causes unrelated to ordinary spider veins.

Who Is Most Likely to Develop Spider Veins?

Anyone can develop spider veins, but certain factors can make them more likely.

Age: Spider veins tend to become more common as we get older because the veins and their valves can become less effective over time.

Family history: Genetics play an important role. If your parents or other close family members have spider veins or varicose veins, you may be more likely to develop them.

Hormonal changes: Changes in hormones can affect the walls of the veins. This may help explain why spider veins are particularly common during pregnancy and certain other periods of hormonal change.

Pregnancy: Pregnancy increases blood volume and places additional pressure on the veins in the pelvis and legs, which can contribute to the development of visible veins.

Prolonged sitting or standing: Staying in one position for long periods can make it more difficult for blood to return efficiently from the legs.

Excess weight: Additional pressure on the veins can make it more difficult for blood to circulate normally through the legs.

Sun exposure: Spider veins can also develop on areas of the body that receive significant sun exposure, particularly the face. These are often different from the spider veins that develop on the legs.

How Are Spider Veins Diagnosed?

Spider veins can often be identified simply by examining the skin. However, if you have symptoms or larger visible veins, your provider may recommend a more thorough vein evaluation.

A lower-extremity venous ultrasound can be used to examine the veins beneath the skin and evaluate how blood is moving through them. Ultrasound can identify abnormal blood flow and determine whether venous reflux is contributing to the visible veins or other symptoms.

This is particularly important when spider veins are accompanied by aching, swelling, heaviness, or varicose veins.

Identifying an underlying source of venous reflux can help determine the most appropriate treatment. Treating only the visible spider veins may not address the underlying problem if abnormal blood flow is present.

How Are Spider Veins Treated?

Spider veins can often be treated with minimally invasive procedures performed in an outpatient setting. The appropriate treatment depends on the size, location, and number of veins being treated, as well as whether there is underlying venous disease.

Sclerotherapy

Sclerotherapy is one of the most common treatments for spider veins. During the procedure, a specialized solution is injected directly into the affected veins.

The solution irritates the inside of the vein, causing it to close. Over time, the body naturally absorbs the treated vessel and blood is redirected through healthier veins.

Sclerotherapy is particularly effective for many of the small spider veins and reticular veins that appear on the legs. Multiple treatment sessions may sometimes be needed, depending on how many veins are present and how they respond to treatment.

Endovenous Ablation

When spider veins are associated with an underlying vein that has significant venous reflux, treating the source of the problem may be an important part of treatment.

Endovenous ablation is a minimally invasive procedure used to close an unhealthy vein that is allowing blood to flow backward. Using ultrasound guidance, a small catheter is inserted into the affected vein and energy is used to seal it closed.

Once the problematic vein is closed, blood naturally redirects through healthier veins. Spider veins can then be treated separately if they remain visible.

Treating Underlying Vein Disease

If an ultrasound shows that spider veins are being influenced by venous reflux, treating the underlying problem may be recommended before or in addition to treating the visible veins.

Depending on the findings, treatment may include endovenous ablation, sclerotherapy, or other minimally invasive vein procedures.

The goal is not simply to make the visible veins disappear. It is to understand why they developed and determine the most appropriate way to treat them.

Can Spider Veins Be Prevented?

There is no guaranteed way to prevent spider veins, particularly when genetics and age are contributing factors. However, maintaining a healthy weight, exercising regularly, and avoiding prolonged periods of sitting or standing can support healthy circulation.

Walking is particularly beneficial because the muscles in your legs help push blood back toward the heart. Taking regular movement breaks during long periods of sitting or standing can also help.

Elevating your legs when resting may help reduce swelling and discomfort. Compression stockings may also help manage symptoms in some people, although they do not eliminate existing spider veins or correct underlying venous reflux.

Even with healthy habits, however, some people will develop spider veins because of factors they cannot control.

When Should You See a Vein Specialist?

If your spider veins are primarily a cosmetic concern, you can choose to have them evaluated whenever you are interested in treatment. You don't have to wait for them to become severe.

A vein evaluation is particularly worthwhile if your spider veins are accompanied by aching, heaviness, swelling, itching, cramping, visible varicose veins, or changes in the skin around your ankles or lower legs.

An evaluation can help determine whether your spider veins are simply superficial blood vessels or whether an underlying vein problem is contributing to their development.

At Thunderbird Vein, we use diagnostic ultrasound when appropriate to evaluate the veins beneath the skin and identify the source of venous problems. Depending on your individual circumstances, treatment may include sclerotherapy, endovenous ablation, or other vein procedures.

Spider veins are common, and in most cases they are not a serious health concern. But if you don't like the way they look—or if they are accompanied by uncomfortable symptoms—you don't necessarily have to live with them. Today's minimally invasive vein treatments can significantly improve the appearance of spider veins while addressing underlying vein problems when they are present.

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