Spider veins are almost always harmless. These tiny red or purple blood vessels visible just beneath the skin are a cosmetic concern for most people, not a medical one. They don’t carry the same risks as varicose veins, and the vast majority of people who have them will never develop complications from them. That said, spider veins can occasionally signal an underlying circulation problem worth investigating.
What Spider Veins Actually Are
Spider veins are dilated blood vessels smaller than 3 millimeters in diameter. They sit close to the skin’s surface and typically appear red, resembling thin tree branches or weblike patterns on the legs or face. Unlike varicose veins, which are larger, ropey, and can cause the skin to bulge outward, spider veins are flat. You can see them under the skin, but you can’t feel them with your fingers.
They’re also remarkably common. In a study of over 1,500 randomly selected adults in Scotland, 88% of women and 79% of men had spider veins on their legs. Most people develop them between ages 30 and 50, and women are about four times more likely than men to get them. Pregnancy is a major driver: the risk increases with each pregnancy, likely because of hormonal shifts and the added pressure on leg veins.
Why They Form
Spider veins develop when tiny blood vessels near the skin lose their ability to snap back to their normal size. Healthy veins have elastic walls that expand and contract to manage blood flow. When that elasticity breaks down, the vessels stay permanently dilated, becoming visible through the skin. Hormones play a significant role, particularly estrogen, which is why pregnancy, birth control, and hormone therapy all increase the likelihood of developing them. Prolonged standing, excess weight, sun exposure, and genetics round out the list of common contributors.
Spider Veins vs. Varicose Veins: The Risk Gap
This distinction matters because the two conditions carry very different risk profiles. Varicose veins involve larger, deeper veins and are associated with measurable health consequences. Genetic research has found a causal link between varicose veins and deep vein thrombosis (DVT), with one population study showing a fourfold increased risk of DVT in patients with varicose veins over a 7.5-year follow-up. No comparable link exists for spider veins alone.
Spider veins sit in the smallest vessels of the venous system. They don’t involve the deeper veins that carry most of your blood back to the heart, and they don’t create the pooling and pressure problems that make varicose veins medically significant. Insurance companies reflect this reality: spider vein treatment is classified as cosmetic unless there’s documented underlying venous insufficiency or bleeding, because spider veins on their own aren’t associated with serious medical complications.
When Spider Veins Can Signal Something Deeper
In a small number of cases, spider veins are the visible surface of a deeper circulation issue. Chronic venous insufficiency, a condition where the valves in your leg veins don’t close properly and blood flows backward, can produce spider veins as one of its earliest signs. If you have spider veins alongside aching, burning, or cramping in your legs, that pattern is worth getting checked. Current vascular surgery guidelines recommend that symptomatic patients with pain, burning, or bleeding from spider veins may benefit from an ultrasound evaluation to rule out problems in the deeper veins.
For people with no symptoms beyond the visible veins themselves, routine imaging isn’t recommended. Guidelines from the Society for Vascular Surgery specifically caution against ultrasound screening for painless spider veins, noting that unnecessary testing can lead to procedures you don’t actually need.
Symptoms That Warrant Attention
Most spider veins produce no physical sensation at all. But there are a few specific situations that should prompt a call to a healthcare provider:
- Swelling, redness, or warmth around a spider vein or any visible blood vessel, which can indicate a blood clot
- Spontaneous bleeding from a spider vein, even minor
- Skin changes nearby such as a rash, sores, or discoloration
- Persistent burning or cramping in the legs, especially after standing
These symptoms don’t necessarily mean something serious is happening, but they can point to venous insufficiency or other conditions that benefit from early treatment.
Treatment Options and What to Expect
Because spider veins are primarily a cosmetic issue, treatment is entirely optional for most people. If you choose to treat them, the two most common approaches are sclerotherapy and laser therapy.
Sclerotherapy involves injecting a solution directly into the vein, causing it to collapse and fade. It’s the more established option, with clearance rates of 50% to 84% after a single treatment in most patients. Full clearance can take up to six sessions. For spider veins smaller than 1 millimeter, laser therapy offers a noninvasive alternative. About 60% of patients see more than 50% clearance after one laser session, and that improves to 80% after two sessions. Slightly larger veins (1 to 2 millimeters) respond less dramatically, with about 67% of patients reaching that same threshold after two treatments.
If there’s an underlying venous insufficiency driving the spider veins, your provider will likely want to address that first. Most insurance plans require a trial of medical-grade compression stockings for about 12 weeks before approving any procedure for venous insufficiency. Spider vein removal itself is rarely covered unless it’s tied to documented symptoms or a deeper vein problem.
Reducing New Spider Veins
You can’t completely prevent spider veins, especially if your genetics or hormonal history put you at higher risk. But a few practical strategies can slow their development. Regular movement helps, particularly if your job keeps you sitting or standing in one position for hours. Compression stockings support blood flow in the legs and are especially useful during pregnancy or long periods of travel. Maintaining a healthy weight reduces the pressure on leg veins, and sunscreen on the face can help prevent the sun-triggered spider veins that commonly appear on the nose and cheeks.
Elevating your legs above heart level for 15 to 20 minutes a day is a simple habit that counteracts the gravitational pooling that contributes to vein dilation over time.