Sclerotherapy is a medical procedure used to treat malformations of blood vessels. The situations that most often require are varicose veins (or varicose veins), telangiectasias and hemorrhoids.

Figure: results of a sclerotherapy operation: before the operation (on the left), after the operation (on the right). From the site:

A sclerotherapy session consists of injecting, inside the malformed vessels (whether veins, venules, arterioles or capillaries), a dose of sclerosing solution capable of causing closure and collapse.

Before the procedure, an objective examination and an accurate analysis of the patient's medical history are required.

In order to appreciate the results of sclerotherapy, it is necessary to wait a few weeks (if the treated blood vessels are small) or a few months (if the treated blood vessels are large).

What is sclerotherapy?

Sclerotherapy is a medical procedure used to treat malformations of blood vessels, such as varicose veins (or varicose veins), spider veins and hemorrhoids.

From a practical point of view, sclerotherapy consists of injecting into the vessel or malformed vessels (be they veins, venules, arterioles or capillaries) a particular solution, capable of causing its closure and collapse. This solution is commonly called " sclerosing solution ".

Once the collapse has occurred, the blood flow is not interrupted, but takes alternative blood vessels.

Sclerotherapy can also be used in case of malformations of the lymphatic vessels, ie the ducts of the human body which carry a transparent or milky substance called lymph .


Figure: ultrasound guided sclerotherapy. The ultrasound probe (white instrument) helps the doctor to identify the vessel in which to inject the drugs by syringe. From the site:

Ultrasound-guided sclerotherapy is a variant of traditional sclerotherapy, which uses an ultrasound scanner to identify the blood vessels to be treated.

In general, ultrasound-guided sclerotherapy is put into practice when the malformations affect vessels located very deep and not visible to the naked eye.

When you run

In most circumstances, sclerotherapy is practiced for aesthetic purposes. For example, it is a very common treatment for the resolution of imperfections due to varicose veins, present on the legs, or to telangiectasias that appear on the face.

However, in some situations, sclerotherapy can also represent an adequate solution to vascular and lymphatic malformations, characterized by:

  • Ache
  • Swelling
  • heartburn
  • Night cramps (when the legs are affected)


Figure: results of a sclerotherapy intervention on varicose veins: before the intervention (on the left), after the operation (on the right). From the site:

According to the WHO (World Health Organization), varicose veins (or varicose veins ) are abnormal and saccular dilations of the veins, especially those of the lower limbs, which often take a tortuous course.


Telangiectasias are harmless dilations of small blood vessels (such as venules, capillaries and arterioles), visible on the skin surface. Similar to sinuous arborescences or to the spider's webs (in English they are called, in fact, "spider veins" that is spider-web veins), they appear with a reddish-blue color and are often the result of an inflammatory process that concerns the skin.


In human anatomy, the term hemorrhoids indicates soft and very vascularized cushions, located in the terminal part of the rectum (which is the last section of the intestine, before the anus).

In medical parlance, the term hemorrhoids also refers to a downward and outward collapse of the rectal mucosa (ie the rectum) in which the hemorrhoids reside.


Sclerotherapy is a fairly safe procedure.

However, in some cases, it can lead to complications of a different nature and variable severity. It can in fact cause temporary problems, which can be solved within a few days / weeks, and potentially very dangerous problems, which require an adequate medical intervention.

Temporary adverse effects

  • Bruises
  • Areas of red and raised skin
  • Small skin irritations
  • Spots or dark lines on the skin
  • Skin covered with tiny bright red blood vessels


Although less frequently, sclerotherapy could cause adverse effects of moderate severity and require appropriate treatment.

These adverse effects are:

  • Inflammatory processes at the injection site level . The area affected by the inflammation can be swollen, painful and hot. In these cases, the doctor usually prescribes anti-inflammatory drugs (NSAIDs) and antibiotics against bacterial infections.
  • Blood clots . A blood clot that forms inside a blood vessel can hinder the passage of blood, compromising the correct spraying of the tissues. The clots that can form after an injection of sclerosing solution can move from the injection site and invade deeper blood vessels, causing a very dangerous phenomenon known as deep vein thrombosis .

    Symptoms of pulmonary embolism:

    • Breathing difficulties (dyspnea)
    • Chest pain
    • Dizziness
    • Hemoptysis (cough with blood)
    Deep vein thrombosis is a possible cause of pulmonary embolism, a condition for which immediate medical intervention is required.
  • Air bubbles in the blood . They can be asymptomatic (that is, free of obvious symptoms) or because of visual problems, headaches, cough and nausea. If you experience such sensations after a sclerosing injection, it is best to contact your doctor.
  • Allergic reactions to the sclerosing reaction .


To understand if sclerotherapy is a viable treatment, the attending physician must subject the patient to an accurate physical examination, also investigating the recent and past clinical history .

Once the suitability for sclerotherapy has been ascertained, it is advisable for the patient, within 24 hours before treatment, to avoid depilating or applying creams on the areas that will then be treated with the sclerosing solution.


During the physical examination, the doctor evaluates the patient's general health and externally analyzes any veins to be treated.


In evaluating the medical history, the doctor investigates whether the patient:

  • He has recently suffered from some pathology; it is particularly important to communicate to the doctor any cardiovascular and / or blood disorders (that is to say concerning the blood).
  • It regularly takes anti-aggregation drugs (aspirin and derivatives), anticoagulants (which thin the blood) or oral contraceptives (which have an opposite effect to anticoagulants and favor the formation of blood clots).
  • He is allergic to some substance.
  • Smokes, because smoking promotes the formation of blood clots.
  • He has already undergone treatments for varicose veins.

All treatments based on antiplatelet agents and anticoagulants must be interrupted a few weeks before starting sclerotherapy; otherwise, there is a risk that the injections will cause serious bleeding.


Sclerotherapy sessions are usually held in the doctor's office and do not require any type of anesthesia.

Usually, one session lasts less than an hour: for injections, a maximum of 10-15 minutes is needed; for the post-injection phase, at least 15-20 are needed.


Just before injecting the sclerosing solution, the doctor places the patient on a couch and carefully cleans the area of ​​skin to be treated with alcohol.

The injections are made with a very thin needle, ideal for any type of blood vessel, even the smallest.

The sclerosing solution - usually composed of polydocanol alcohol, sodium tetradecyl sulfate, sodium salicylate and chromed glycerin - acts by closing the malformed vessel and causing it to collapse and then disappear. The blood circulation is not affected by these changes, because the blood takes an alternative route and continues to perform its normal functions.

After the injection, to allow a better diffusion of the sclerosing solution, the doctor gently compresses and massages the entire affected area.

The number of injections depends on the amount of malformed veins and their size: therefore, the larger the blood vessel or the area to be treated, the more injections will be.

The liquid and foamy sclerosing solution

The sclerosing solution can occur both in the form of liquid and foam . The foamy preparation is very effective, especially for large venous vessels.


The injections may cause pain or brief spasms. If the intensity of these disorders is high, it should be reported to the doctor who is performing the treatment, because it could mean that the sclerosing solution has been applied incorrectly.


At the end of the compression and massage phases, the patient is monitored for 15-20 minutes, to see how he responds to treatment. After that, he can go home.

For at least two or three weeks, your doctor recommends avoiding excessive exposure to sunlight, because it could cause the appearance of dark spots on the skin.

If sclerotherapy was performed on varicose veins present on the legs

After 15-20 minutes of monitoring, it is good to walk and move your legs for several minutes, so as to prevent the formation of blood clots inside the venous vessels.

Furthermore, for about three weeks, it is advisable to apply compression bandages or elastic stockings, to maximize the results of the injections. The return to normal daily activities is immediate: it is only advised not to drive immediately after the session and to avoid excessive efforts for a week or two.


On small blood vessels, sclerotherapy results are noticeable after 3-6 weeks; on large vessels, on the other hand, they are visible only after 3-4 months.

In any case, after 30 days from the session, it is necessary to make a control visit to evaluate the response to the therapy.

In some cases, it is possible to repeat the treatment: in similar situations, it is necessary to spend 4-6 weeks between one session and another.

Compared to surgery for varicose veins, sclerotherapy is certainly less invasive, but further studies are needed to assess its long-term effects.