What is sclerotherapy

Sclerotherapy involves injecting a solution of either salt water (hypertonic saline 20% NaCl) or a chemical solution (e.g. sodium tetradecyl sulphate or polidocanol) directly into the varicose or spider vein that causes them to collapse permanently. Sclerotherapy uses injections from a very fine, thin needle to improve the cosmetic appearance of spider veins, treat small varicose veins in the legs, and relieve related symptoms such as aching, burning, swelling and cramping. The sclerotherapy solution causes the vein walls to swell, stick together and seal shut, stopping the flow of blood, forcing blood to reroute through healthier veins. The collapsed vein is reabsorbed into local tissue and eventually fades within a few weeks.

Larger varicose veins may also be treated by sclerotherapy. This is the best method for varicose veins if they are tortuous or recurrent (endovenous laser treatment may be preferred for stright veins or on the first occasion). First a Duplex ultrasound scan should be performed to map out the path of superficial, perforator and deep veins. Those greater than 5mm in width and demonstrating reflux are the most suitable for treatment. Sclerotherapy of larger superficial veins and perforator vessels is usually performed with ultrasound (echo) guidance. Best results are achieved using a foam sclerosant, where the sclerosant solution is mixed with air in a ratio of 1: 4 to form minute bubbles. This provides a greater volume to push the blood away so the sclerosant may adhere more effectively to the blood vessel wall.

Most often sclerotherapy is used to treat leg veins, but sclerotherapy may also be used for venous malformation, or blue vessels on the sides of the nose and elsewhere. No anaesthetic is required. A strong solution (the sclerosant) is injected directly into the blood vessel causing inflammation of the walls of the vessel. The vessel disappears over a few weeks to months.

Sclerotherapy is the most common treatment for improving the appearance of varicose and spider veins on the legs. Sclerotherapy is often considered the treatment of choice for small varicose veins. Each treatment session typically results in elimination of 50 to 80 percent of the injected veins. Repeated treatments may be necessary at six- to twelve-weekly intervals to achieve up to 85% success at three years.

Although each session may involve a large number of injections, the needle used is very fine so that pain is not generally a problem. There may be some stinging as the solution travels through the smaller vessels. These become red and slightly swollen, sometimes itchy for a few hours.

The number of veins treated in one session varies, and depends on the size and location of the veins. The procedure is usually completed within 30 to 45 minutes.

After sclerotherapy, treated veins tend to fade within a few weeks, although occasionally it may take a month or more to see the full results. In some instances, several sclerotherapy treatments may be needed.

Varicose veins are caused by weak or damaged valves in the veins. The heart pumps oxygen-rich blood to the body through the arteries. Veins then carry the blood from the body back to the heart. As your leg muscles squeeze, they push blood back to the heart from your lower body against the flow of gravity.

Veins have valves that act as one-way flaps to prevent blood from flowing backwards as it moves up your legs. If the valves become weak, blood can leak back into the veins and collect there, causing veins to enlarge and become varicose.

Spider veins can develop from weak or damaged valves as well. They can also be caused by hormone changes, exposure to sun and injuries.

If you are considering sclerotherapy, you will meet with a dermatologic surgeon for a consultation to discuss your cosmetic goals and to determine if sclerothereapy is the best approach to meet your needs. Your surgeon will examine the veins you would like treated, and will also examine you for evidence of more serious venous problems. Photographs may be taken for before and after results.

You will also discuss your medical history, including previous surgeries, present and past health problems, medications, and nutritional and herbal supplements you are taking or have taken at some time.

If you decide to have sclerotherapy, your doctor will give you specific instructions to follow before surgery. Your doctor will also review any medications you regularly take and tell you if you need to stop taking them before treatment.

Your doctor may recommend that you wear compression stockings after sclerotherapy to help with healing and decrease swelling. You will be told where you can buy them before your procedure.

Reasons for sclerotherapy

Sclerotherapy is often done for:

  • Cosmetic purposes — to improve the appearance of varicose and spider veins

Sclerotherapy procedure also can improve related symptoms such as:

  • Aching
  • Swelling
  • Burning
  • Night cramps

If you’re pregnant or breast-feeding, doctors recommend waiting to have sclerotherapy done.

What are varicose veins and spider veins?

Varicose veins are enlarged veins that can be blue, red, or flesh-colored. They often look like cords and appear twisted and bulging. They can be swollen and raised above the surface of the skin. Varicose veins are often found on the thighs, backs of the calves, or the inside of the leg. During pregnancy, varicose veins can form around the vagina and buttocks.

Spider veins are like varicose veins but smaller. They also are closer to the surface of the skin than varicose veins. Often, they are red or blue. They can look like tree branches or spiderwebs with their short, jagged lines. They can be found on the legs and face and can cover either a very small or very large area of skin.

What causes varicose veins and spider veins?

Varicose veins can be caused by weak or damaged valves in the veins. The heart pumps blood filled with oxygen and nutrients to the whole body through the arteries. Veins then carry the blood from the body back to the heart. As your leg muscles squeeze, they push blood back to the heart from your lower body against the flow of gravity. Veins have valves that act as one-way flaps to prevent blood from flowing backwards as it moves up your legs. If the valves become weak, blood can leak back into the veins and collect there. (This problem is called venous insufficiency.) When backed-up blood makes the veins bigger, they can become varicose.

Spider veins can be caused by the backup of blood. They can also be caused by hormone changes, exposure to the sun, and injuries.

Many factors increase a person’s chances of developing varicose or spider veins. These include:

  • Increasing age. As you get older, the valves in your veins may weaken and not work as well.
  • Medical history. Being born with weak vein valves increases your risk. Having family members with vein problems also increases your risk. About half of all people who have varicose veins have a family member who has them too.
  • Hormonal changes. These occur during puberty, pregnancy, and menopause. Taking birth control pills and other medicines containing estrogen and progesterone also may contribute to the forming of varicose or spider veins.
  • Pregnancy. During pregnancy, there is a huge increase in the amount of blood in the body. This can cause veins to enlarge. The growing uterus also puts pressure on the veins. Varicose veins usually improve within 3 months after delivery. More varicose veins and spider veins usually appear with each additional pregnancy.
  • Obesity. Being overweight or obese can put extra pressure on your veins. This can lead to varicose veins.
  • Lack of movement. Sitting or standing for a long time may force your veins to work harder to pump blood to your heart. This may be a bigger problem if you sit with your legs bent or crossed.
  • Sun exposure. This can cause spider veins on the cheeks or nose of a fair-skinned person.

How can I prevent varicose veins and spider veins?

Not all varicose and spider veins can be prevented. But, there are some steps you can take to reduce your chances of getting new varicose and spider veins. These same things can help ease discomfort from the ones you already have:

  • Wear sunscreen to protect your skin from the sun and to limit spider veins on the face.
  • Exercise regularly to improve your leg strength, circulation, and vein strength. Focus on exercises that work your legs, such as walking or running.
  • Control your weight to avoid placing too much pressure on your legs.
  • Don’t cross your legs for long times when sitting. It’s possible to injure your legs that way, and even a minor injury can increase the risk of varicose veins.
  • Elevate your legs when resting as much as possible.
  • Don’t stand or sit for long periods of time. If you must stand for a long time, shift your weight from one leg to the other every few minutes. If you must sit for long periods of time, stand up and move around or take a short walk every 30 minutes.
  • Wear elastic support stockings and avoid tight clothing that constricts your waist, groin, or legs.
  • Avoid wearing high heels for long periods of time. Lower-heeled shoes can help tone your calf muscles to help blood move through your veins.
  • Eat a low-salt diet rich in high-fiber foods. Eating fiber reduces the chances of constipation, which can contribute to varicose veins. High-fiber foods include fresh fruits and vegetables and whole grains, like bran. Eating less salt can help with the swelling that comes with varicose veins.

Are varicose veins and spider veins dangerous?

Spider veins rarely are a serious health problem, but they can cause uncomfortable feelings in the legs. If there are symptoms from spider veins, most often they will be itching or burning. Less often, spider veins can be a sign of blood backup deeper inside that you can’t see on the skin. If so, you could have the same symptoms you would have with varicose veins.

Varicose veins may not cause any problems, or they may cause aching pain, throbbing, and discomfort. In some cases, varicose veins can lead to more serious health problems. These include:

  • Sores or skin ulcers due to chronic (long-term) backing up of blood. These sores or ulcers are painful and hard to heal. Sometimes they cannot heal until the backward blood flow in the vein is repaired.
  • Bleeding. The skin over the veins becomes thin and easily injured. When an injury occurs, there can be significant blood loss.
  • Superficial thrombophlebitis, which is a blood clot that forms in a vein just below the skin. Symptoms include skin redness; a firm, tender, warm vein; and sometimes pain and swelling.
  • Deep vein thrombosis (DVT), which is a blood clot in a deeper vein. It can cause a “pulling” feeling in the calf, pain, warmth, redness, and swelling. However, sometimes it causes no significant symptoms. If the blood clot travels to the lungs, it can be fatal.

Is sclerotherapy safe?

Yes, sclerotherapy is a simple and typically safe procedure. In most cases, the pain, discomfort and swelling associated with the veins disappears within days, and the vessels slowly resolve over several months.

  • Any procedure where the skin is penetrated carries a risk of infection. The chance of infection requiring antibiotic treatment appears to be less than one in 1,000.
  • Risks include the formation of blood clots in the veins, severe inflammation, adverse allergic reactions to the sclerosing solution and skin injury that could leave a small but permanent scar.

Larger injected varicose veins may become lumpy and/or hard for several months before resolving. Raised red areas may appear at the injection sites and should disappear within a few days. Brown lines or spots on the skin may be seen at the injection sites. In most cases, they disappear within three to six months, but can be permanent about five percent of the time. Bruising may occur around the injection site and can last several days or weeks.

In general, spider veins respond to sclerotherapy in three to six weeks, and larger veins respond in three to four months. If the veins respond to the treatment, they will not reappear. However, new veins may appear over time, and if needed, you may return for additional injections.

Is sclerotherapy painful?

You will feel small needle sticks and possibly a mild burning sensation. And you may experience a cramping sensation for one to two minutes when larger varicose veins are injected.

What are the limitations of sclerotherapy?

Large varicose veins do not respond as well as small ones to sclerotherapy. A few (less than 10 percent) of people who have sclerotherapy do not respond to the injections at all. In these instances, different solutions or a different method, such as cutaneous laser therapy, may be attempted.

You will not be able to undergo sclerotherapy treatment if you are pregnant, breastfeeding, or are bedridden. You must wait at least three months after giving birth before you can be considered for this procedure.

Often, phlebectomy is used with a more comprehensive treatment plan, including additional procedures such as endovenous catheter ablation that use radiofrequency or laser energy.

You should discuss your individualized treatment plan with your provider.

Sclerotherapy side effects

Serious complications following sclerotherapy are rare. However, as with any procedure, it does carry some risk and may cause side effects.

  • Allergy from the sclerosant (this does not occur with hypertonic saline).
  • Ulceration. This will eventually heal leaving a small scar, or may be removed surgically. If an artery is inadvertently treated, the surrounding tissue may die (necrose), which is potentially serious.
  • Deep venous thrombosis. The risk is very small when venules are treated but it occasionally follows sclerotherapy of larger varicose veins. It is more likely in those predisposed to blood clotting through inherited thrombophilia, lack of exercise, air travel, after major operations and other reasons. Deep venous thrombosis may rarely lead to potentially serious pulmonary emboli (clots in the blood vessels of the lungs) in about 1 in every ten thousand procedures.

Temporary side effects that may occur at the injection site include:

  • Stinging or pain at the sites of injection
  • Swelling of the ankles or feet, or muscle cramps

The following occur more frequently:

  • Staining or brown pigmentation, at the site or along the line of the vein. This occurs in about 30% of patients. In most cases this resolves but it may take many months.
  • Clots within treated vessels. These are not dangerous but can be quite tender if they occur in the larger veins. They can be removed through a needle prick after several weeks if necessary, but left alone they will eventually be reabsorbed.
  • Temporary bruising. Bruises at the injection sites are quite common but resolve within a week or so.
  • Capillary matting (multiple tiny red blood vessels). This is an increase in the number of fine red vessels around the injection site: it may disappear on its own, or can be treated by further injections or a vascular laser.

Very fine vessels may be too small to inject, in which case a vascular laser or intensed pulsed light treatment may be worth trying.

These side effects usually occur when hypertonic saline solution is used

  • Red, raised areas at the injection sites

These are similar to hives, and should disappear within a day or so.

  • Brown lines or spots on the skin at the injection sites

Darkened areas may result when blood escapes from treated veins. They are probably formed from iron in the blood. These dark areas occur more often in patients who have larger veins or patients who tan easily. In most cases they disappear within a year, but they may last longer.

  • Groups of fine red blood vessels near the injection sites of larger vessels

About one-third of patients develop groups of vessels, especially on the thighs. Most disappear by themselves, some need additional injection treatments or laser therapy, and a few vessels may not disappear with treatment.

  • Small, painful ulcers at treatment sites, which may develop immediately following treatment or after a few days

These occur when some of the solution escapes into the surrounding skin or enters a small artery at the treatment site. They can be successfully treated, but it is important to tell your dermatologist immediately if they develop.

  • Temporary bruises

Bruises usually occur after laser treatments and are probably related to the thinness of blood vessel walls. They usually disappear in a few weeks. Occasionally, bruising occurs after sclerotherapy.

  • Allergic reactions to sclerosing solutions

Although allergic reactions are uncommon, they can be treated. Inform your dermatologist immediately if you do experience an allergic reaction.

  • Inflammation of treated blood vessels

This is very unusual but can be treated with medications such as aspirin, compression, antibiotics or heat.

  • Lumps in injected vessels

Lumps are caused by coagulated blood. They are not dangerous and may be drained by your dermatologist a few weeks after injection.

  • Burning with discoloration of the skin

Side effects that may require treatment

Other complications are less common but may require treatment. These include:

  • Inflammation. This is usually mild but may cause swelling, warmth and discomfort around the injection site. Your doctor may suggest aspirin to reduce the inflammation.
  • Blood clot. A lump of clotted blood may form in a treated vein that may require drainage. Rarely, a blood clot may travel to a deeper vein in your leg (deep vein thrombosis). Deep vein thrombosis (DVT) carries a risk of pulmonary embolism (a very rare complication of sclerotherapy), an emergency situation where the clot travels from your leg to your lungs and blocks a vital artery. Seek immediate medical care if you experience difficulty breathing, chest pain or dizziness, or you cough up blood.
  • Air bubbles. Tiny air bubbles may rise in your bloodstream. These don’t always cause symptoms, but if they do, symptoms include visual disturbances, headache, fainting and nausea. These symptoms generally go away, but call your doctor if you experience problems with limb movement or sensation after the procedure.
  • Allergic reaction. It’s possible that you may have an allergic reaction to the solution used for treatment, but this is uncommon.

How should I prepare for a sclerotherapy

Before the sclerotherapy procedure, your doctor performs a physical exam and gathers your medical history.

Medical history

Your doctor will want to know your medical history, including asking about any:

  • Recent illnesses or existing medical conditions, such as a heart condition or a past history of blood clots
  • Medications or supplements you take, especially aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs), blood thinners or herbal supplements
  • Allergies especially to local anesthetic medications, general anesthesia or to contrast materials containing iodine (sometimes referred to as “dye” or “x-ray dye”)
  • Previous treatment for varicose veins and the results of the treatment

Tell your doctor if there’s a possibility you are pregnant and discuss any recent illnesses, medical conditions, allergies and medications you’re taking, including herbal supplements and aspirin. You may be advised to stop taking aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs), iron supplements, or blood thinners several days prior to your procedure.

  • You may be asked to stop taking iron supplements.
  • Also inform your doctor about recent illnesses or other medical conditions.
  • Ask your doctor about antibiotic medications you may be taking or ask for safe guidelines for discontinuing these medications.
  • No lotion should be applied to legs before or after sclerotherapy.
  • You should wear comfortable, loose-fitting clothing to your exam. You may be given a gown to wear during the procedure.
  • You may want to bring a pair of shorts to wear during the procedure.

Do not apply lotion to your legs before or after sclerotherapy. Leave jewelry at home and wear loose, comfortable clothing. Since you may be asked to wear a gown, you may want to bring a pair of shorts to wear during the procedure.


Depending on which veins are involved, your doctor may request ultrasound imaging on the veins in your legs. Ultrasound is a painless procedure that uses sound waves to produce images of structures inside the body.

Sclerotherapy procedure

Sclerotherapy procedure is often done on an outpatient basis. However, some patients may require admission following the procedure. Please consult with your physician as to whether or not you will be admitted. Sclerotherapy does not require anesthesia and is typically performed in your dermatologic surgeon’s office. The procedure takes about 15 to 30 minutes, but the exact length of time depends on the size of the area and the number of veins being treated.

Depending on its size, a single vein may have to be injected more than once. Treatment must be performed weeks or months apart. Multiple veins may be injected during one treatment session.

During the procedure, you’ll lie on your back with your legs slightly elevated. Your doctor will cleanse the area to be treated before inserting a sclerosing solution into the targeted vein with a fine needle. The solution displaces the blood and reacts with the vascular endothelium causing the vein walls to swell, stick together and scarring the vein, stopping the flow of blood. As a result, the vein fades within a few weeks.

A variety of products are used, including hyperosmotic solutions (e.g., hypertonic saline), detergent solutions (e.g., sodium tetradecyl sulfate), and corrosive agents (e.g., glycerin). Injections typically work better on small (1 to 3 mm) and medium (3 to 5 mm) veins; however, a precise diameter used to make treatment decisions is lacking. Although sclerotherapy is a clinically effective and cost-effective treatment for smaller varicose veins, concerns about the development of deep venous thrombosis and visual disturbances, and the recurrence of varicosities have been noted 1.

You may experience some minor stinging or cramps when the needle is inserted into the vein. Be sure to tell your doctor if you have any discomfort. Some people experience minor stinging or cramps when the needle is inserted into the vein. If you have a lot of pain, tell your doctor. Pain may occur if the solution leaks from the vein into surrounding tissue.

After the injections, your doctor will apply compression and massage the treated area to keep blood out of the injected vein and disperse the solution. A compression pad may be taped onto the injection site to keep the area compressed while your doctor moves on to the next vein.

The number of injections depends on the number and size of veins being treated.

Sclerotherapy aftercare

Often cotton wool pads under adhesive plasters are applied to the injection sites. Pressure is applied to the treated vessels using Grade 2 graduated compression hosiery (support stockings) and/or bandages. These are usually worn for between seven days and three weeks following each treatment. They come in different sizes and colors.

You’ll be able to get up and walk around soon after the procedure. Walking and moving your legs is important to prevent the formation of blood clots.

Patients are usually able to return to normal daytime activities immediately after sclerotherapy. They should walk for at least thirty minutes a day, especially for the first few days following the procedure. Vigorous physical activities such as weight lifting or aerobics classes are not advised during this time.

Sclerotherapy recovery

After the procedure, it is important to walk around to prevent formation of blood clots in your legs. Most people return to their normal activities on the same day, but it may be wise to have someone drive you home after the procedure. Your doctor will probably advise you to avoid strenuous exercise for two weeks after the procedure.

You’ll also want to avoid sun exposure to the treated areas during that time. The inflammation caused by the injections combined with sun exposure can lead to dark spots on your skin, especially if you already have a dark skin tone.

Your doctor will give you specific instructions to follow for recovery, including:

  • Avoid sun exposure to the treated areas for two weeks after the procedure. The inflammation caused by the injections combined with sun exposure can lead to dark spots on your skin, especially if you already have a dark skin tone.
  • Wear compression stockings to maintain compression on the treated veins.

You’ll be asked to wear compression stockings or bandages — usually for about two weeks — to maintain compression on the treated veins.

Sclerotherapy before and after

If you were treated for small varicose veins or spider veins, you can usually expect to see definitive results in three to six weeks. Larger veins may require three to four months. However, multiple treatments may be needed to achieve the results you want.

Veins that respond to treatment generally don’t come back, but new veins may appear.

Your doctor will likely schedule a follow-up visit about a month after the procedure to check the procedure’s success and decide whether further sessions are needed. Generally, you need to wait about six weeks before undergoing another sclerotherapy session.

Studies of sclerotherapy as a treatment for varicose and spider veins indicate that it has an overall success rate of about 60 to 80 percent in eliminating treated veins.

sclerotherapy before and after
sclerotherapy before and after
sclerotherapy before and after
  1. Campbell B. Varicose veins and their management. BMJ. 2006;333(7562):287–292.[]
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