Sclerotherapy is a minimally invasive procedure that eliminates varicose veins and spider veins by injecting a solution directly into the affected blood vessel. The solution damages the inner lining of the vein, causing it to collapse, seal shut, and eventually be reabsorbed by the body. It’s the most common treatment for spider veins on the legs and is also used for smaller varicose veins.
How Sclerotherapy Works
The injected solution, called a sclerosant, works by destroying the cells lining the inside of the vein. Once those cells are damaged, the vein walls become inflamed, stick together, and scar closed. Blood reroutes through healthier veins nearby, and the treated vein gradually fades from view over the following weeks.
Different types of sclerosants damage veins in slightly different ways. Detergent-based agents, which are the most commonly used in the U.S., break apart cell membranes. Osmotic agents work by rapidly dehydrating the cells lining the vein. Corrosive agents destroy the cell membranes directly, leading the vein to scar shut. The end result is the same: the vein is permanently closed off and absorbed by surrounding tissue.
What Sclerotherapy Treats
The primary use is treating spider veins (the tiny red or purple web-like veins visible just under the skin) and reticular veins (slightly larger bluish veins, typically 1 to 3 mm in diameter). These are most common on the legs and thighs. Sclerotherapy can also treat some smaller varicose veins, though larger or deeper varicose veins often require different approaches.
Beyond cosmetic concerns, sclerotherapy is sometimes used when spider or varicose veins cause aching, swelling, burning, or nighttime leg cramps. It has also been applied to treat venous ulcers, particularly when other surgical options carry too much risk for patients with other health conditions.
Liquid vs. Foam Sclerotherapy
Traditional sclerotherapy uses a liquid solution injected with a fine needle. This works well for spider veins and very small veins close to the surface. For larger or deeper veins, providers often use a foam version of the same solution. The foam displaces blood inside the vein more effectively than liquid, allowing the sclerosant to make better contact with the vein walls.
Foam sclerotherapy is frequently performed with ultrasound guidance, which lets the provider watch the foam travel through the vein in real time. This precision reduces the chance of the solution leaking outside the target vein and helps ensure the right amount reaches the full length of the vessel. Ultrasound-guided foam sclerotherapy has been shown to cause less pain and faster recovery compared to traditional vein surgery, and it doesn’t require any anesthesia.
What to Expect During the Procedure
A typical session lasts 30 to 45 minutes. You’ll lie down, and the provider will use very fine needles to inject the sclerosant into each targeted vein. The number of injections per session varies based on how many veins are being treated and their size and location. Some people describe a mild burning or cramping sensation at the injection site that fades within a few minutes.
No general anesthesia or sedation is needed. You can walk immediately after the procedure and drive yourself home. Most people return to normal activities the same day, though you’ll want to avoid strenuous exercise for a short period.
Recovery and Aftercare
Compression is the most important part of aftercare. You’ll typically wear compression bandages or stockings continuously for the first five days (removing them only to shower), then switch to medium-weight compression stockings during the day for one to two weeks after that. The compression helps the treated vein walls stay sealed together and reduces swelling and bruising.
Walking regularly after the procedure is encouraged because it promotes blood flow through the remaining healthy veins. Most providers recommend avoiding hot baths, direct sun exposure on treated areas, and heavy lifting for the first week or two. Treated spider veins usually begin to fade within three to six weeks, while larger veins can take three to four months to fully disappear. Some veins require more than one treatment session.
Side Effects and Risks
The most common side effect is skin darkening (hyperpigmentation) along the path of the treated vein. This occurs in up to 30% of cases, depending on the technique used, the type of sclerosant, and individual skin tone. The discoloration is usually temporary, fading over several months, though it can occasionally persist longer.
Bruising around injection sites is normal and typically resolves within a couple of weeks. Some people notice small, firm lumps where the vein was treated. These are trapped blood that the body gradually reabsorbs. Other possible but less common effects include mild itching, redness, or temporary swelling near the injection site.
Serious complications are rare. They include allergic reactions to the sclerosant, formation of blood clots in deeper veins, and very rarely, skin ulceration at the injection site. The risk of these complications is lower when the procedure is performed by an experienced provider using appropriate concentrations for the vein size being treated.
Who Should Avoid Sclerotherapy
Sclerotherapy is not recommended during pregnancy. People with a history of blood clots in deep veins need careful evaluation before proceeding, as the procedure involves deliberate inflammation inside blood vessels. Those with known allergies to common sclerosing agents, active skin infections over the treatment area, or certain clotting disorders may also be poor candidates. Your provider will review your medical history and any medications, particularly blood thinners, before clearing you for treatment.
Cost and Insurance Coverage
The average cost of a sclerotherapy session is around $500, according to the American Society of Plastic Surgeons. That figure covers the provider’s fee only, not additional costs like ultrasound guidance or follow-up visits. The total price depends on how many sessions you need and the technique used. Most people require two to four sessions to achieve their desired results.
When sclerotherapy is performed for cosmetic reasons (spider veins that don’t cause symptoms), most insurance plans won’t cover it. If there’s a documented medical need, such as significant pain, swelling, or skin changes from venous insufficiency, some insurers will cover the procedure after conservative treatments like compression stockings have been tried first. It’s worth checking your specific plan before scheduling.