Definition & Overview

Sclerotherapy is an ultrasound-guided medical procedure that involves injecting a salt solution into a vein to cause it to shrink and collapse. Just like radiofrequency and laser ablation, it is used for the treatment of vascular and lymphatic malformations, such as spider and varicose veins and even haemorrhoids.

Who Should Undergo and Expected Results

As mentioned above, sclerotherapy is for patients with vascular or venous malformations such as spider and varicose veins and haemorrhoids. It is often prescribed when patients experience symptoms such as swelling, a burning sensation, and night cramps. It can also be offered to those who are bothered by the appearance of their spider or varicose veins.

The sclerosing solution used in the procedure gradually shrinks the affected veins and closes the feeder veins, thereby reducing the likelihood of recurrences. For this reason, sclerotherapy is widely preferred over laser therapy.

How is the Procedure Performed?

Prior to a sclerotherapy, the patient is subjected to a thorough physical examination, and the affected vein is carefully examined, usually with the use of ultrasound imaging, to rule out the presence of underlying blood vessel disease as well as existing medical conditions and allergies that may complicate the procedure.

The doctor then proceeds by using 30-gauge needles to inject the sclerosing agent precisely and slowly into the affected veins. Each injection delivers around 0.1 to 0.4 mL of the solution and is injected at an interval of 2 to 3 cm until the entire vessel has been treated.

There are three main types of sclerosants, namely:

Detergents, which disrupt the vein’s cellular membrane * Sodium tetradecyl sulfate, which is the most commonly used agent * Polidocanol * Sodium morrhuate * Ethanolamine oleate

Osmotic agents, which damage the cell by shifting its water balance * Hypertonic sodium chloride solution * Sodium chloride with dextrose

Chemical irritants, which damage the cell wall by destroying the endothelium * Chromated glycerin * Polyiodinated iodine

After the injection, the needle is carefully removed and the area is compressed with a bandage or a graduated compression stocking. Patients are then advised to perform exercises to strengthen their lower extremities, but should avoid aggressive movements for at least four weeks after the procedure.

Possible Risks and Complications

Although it is a simple, non-invasive procedure that can effectively get rid of varicose and spider veins, sclerotherapy can still cause some complications. These complications range from temporary side effects that resolve on their own without treatment to some more serious side effects that may necessitate further treatment.

Temporary side effects, which can take days, weeks, or sometimes even months or years to disappear completely, include:

  • Raised red areas
  • Small skin sores
  • Bruising
  • Multiple tiny red blood vessels that show through the skin
  • Darkened skin or pigmentation
  • Lines or spots in the skin

Meanwhile, more serious complications that require treatment include:

  • Blood clots
  • Inflammation
  • Allergic reaction to the solution used, which may cause urticarial or anaphylaxis
  • Air bubbles in the bloodstream
  • Oedema
  • Deep vein thrombosis
  • Myocardial infarction

Wearing graduated compression stockings with a strength of around 30 mm Hg will help reduce the risk of these serious complications from occurring. The stockings should be worn daily for up to 3 weeks, starting from the very first night following the procedure.


  • Alaiti, S. “Sclerotherapy treatment and management.” Medscape.

  • Cheng D., Amin P., Thuong Van Ha. “Percutaneous sclerotherapy of cystic lesions.” Semin. Intervent. Radiol. 2012 Dec; 29(4): 295-300.

  • Snow T., McEntee JP., Greaves SC., White HD. “Myocardial infarction following sclerotherapy in a patient with a patent foramen ovale.” The New Zealand Medical Journal. 2012 Nov; 125(1366).

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