Spider veins: causes and treatment

Spider veins are small, visible blood vessels that appear near the skin surface as red, blue, or purple lines or web-like clusters. They are very common, especially on the legs, and they affect both men and women across a wide age range. This article explains what causes spider veins, how they differ from varicose veins, and what treatment looks like.

What are spider veins?

Spider veins (known medically as telangiectasias) are tiny dilated blood vessels visible just beneath the skin. They are typically less than 1 millimeter in diameter and do not protrude above the skin surface the way varicose veins do. They appear as short lines, branching patterns, or web-like clusters, ranging in color from red to blue-purple depending on their depth.

An important note: spider veins and varicose veins are not always independent conditions. In some patients, spider veins are fed by underlying venous insufficiency. A duplex ultrasound can determine whether there is a deeper cause. Book a consultation to have yours imaged.

What causes spider veins?

Spider veins develop when small blood vessels near the skin surface dilate permanently. Several factors contribute:

• Family history. A genetic tendency toward weakened vessel walls is the most consistent risk factor.
• Hormonal changes. Estrogen is thought to weaken vessel walls. Spider veins are more common in women and often first appear during pregnancy, around menopause, or with hormonal contraception.
• Prolonged sitting or standing. Sustained pressure in the lower legs promotes vessel dilation.
• Vessel walls naturally thin and lose elasticity over time.
• Prior trauma or injury. Bruising or local trauma can leave persistent dilated vessels.
• Underlying venous insufficiency. When deeper veins carry excess pressure from failing valves, that pressure can transmit outward to smaller surface vessels.

What causes spider veins?

Spider veins develop when small blood vessels near the skin surface dilate permanently. Several factors contribute:

• Family history. A genetic tendency toward weakened vessel walls is the most consistent risk factor.
• Hormonal changes. Estrogen is thought to weaken vessel walls. Spider veins are more common in women and often first appear during pregnancy, around menopause, or with hormonal contraception.
• Prolonged sitting or standing. Sustained pressure in the lower legs promotes vessel dilation.
• Vessel walls naturally thin and lose elasticity over time.
• Prior trauma or injury. Bruising or local trauma can leave persistent dilated vessels.
• Underlying venous insufficiency. When deeper veins carry excess pressure from failing valves, that pressure can transmit outward to smaller surface vessels.

Are spider veins a medical concern?

Spider veins are not dangerous on their own, but they are not purely cosmetic either. Many patients experience real symptoms, and some spider veins are a surface sign of underlying venous insufficiency that changes both the treatment approach and insurance coverage.

Patients with spider veins often experience burning, itching, or aching in the affected area. When these symptoms are present, treatment can provide meaningful relief. The only way to know whether there is an underlying cause driving the surface veins is a clinical evaluation, and our team does not pre-judge the answer before seeing your imaging. Book a consultation to find out whether your spider veins have an underlying medical cause.

How spider veins are treated

The primary treatment for spider veins is sclerotherapy. A small amount of medical solution (the sclerosant) is injected into the targeted vein using a very fine needle. The solution irritates the inner vein wall, causing the walls to seal together. Over the following weeks, the body absorbs the treated vessel and it fades from view. A single session typically treats multiple vessels. Procedures involve minimal discomfort. Most patients describe a brief stinging sensation that passes quickly and return to normal activities the same day.

What results look like

Spider veins do not disappear immediately after sclerotherapy. Treated vessels typically begin to fade over two to six weeks. New spider veins can develop over time because the underlying tendency toward vessel dilation continues. Periodic re-evaluation and maintenance treatment can address new vessels as they appear.

If you would like to know whether your spider veins are a standalone concern or connected to an underlying condition, a consultation is the right next step. Book a consultation to have your veins mapped and evaluated properly.

When spider veins signal an underlying cause

Not every cluster of spider veins points to a deeper problem. However, when spider veins appear in certain patterns, particularly on the inner ankle and inner lower leg, they can indicate underlying venous insufficiency in the great saphenous vein. These patterns are sometimes called "corona phlebectatica" and represent the surface expression of chronic venous pressure. In patients with this distribution, treating only the surface veins without addressing the underlying reflux produces incomplete results and a high rate of recurrence.

Our evaluation process identifies this relationship when it exists. If a duplex ultrasound reveals that your spider veins are being fed by a failing deeper vein, your treatment plan will address the reflux source before or alongside the surface treatment. This is one of the key reasons why a clinical evaluation matters even for spider veins that seem straightforward.

What patients should know before their first visit

Before your first appointment, it helps to note which areas of your legs are affected and whether you have any symptoms: burning, itching, aching, or swelling. Bring a list of any medications you are currently taking, and be ready to describe whether you have a family history of vein disease. If you have had prior sclerotherapy or other vein treatment elsewhere, bring any records you have. This background helps your evaluation be as efficient and accurate as possible. Our team will take it from there.

Frequently asked questions

Can I treat spider veins at home?

There are no home treatments that close spider veins. Compression stockings can reduce the pressure contributing to new vessel dilation and may reduce symptoms, but they do not close existing spider veins. Sclerotherapy performed by a vein specialist is the standard clinical treatment.

Will insurance cover spider vein treatment?

Spider vein treatment is generally considered cosmetic and not covered by most insurance plans unless symptoms can be clinically documented and an underlying medical cause is identified. A clinical evaluation is the only way to determine whether your specific situation qualifies for coverage.

How many sclerotherapy sessions will I need?

The number of sessions depends on the extent of spider veins and whether underlying venous insufficiency is contributing. Some patients see satisfactory results in one or two sessions; others with more widespread spider veins may need three or more. Your treatment plan is individualized based on your evaluation findings.

Is there any downtime after sclerotherapy?

There is zero downtime. Most patients return to normal activities the same day. Strenuous exercise is typically avoided for a few days, and compression is worn for a period after treatment to support healing.

Do spider veins come back after sclerotherapy?

Successfully treated vessels typically do not recur in the same spot. However, the underlying tendency toward small vessel dilation continues, and new spider veins can form over time in other areas. When underlying venous insufficiency is identified and treated alongside surface treatment, the rate of new spider vein formation in the same region is substantially reduced.