Sclerotherapy and Microfoam Treatment for Varicose Veins
Sclerotherapy is one of the most versatile minimally invasive treatments used in modern varicose vein care. It can be used for small spider veins, reticular veins, larger varicose tributaries, recurrent veins and, in selected patients, refluxing truncal veins.
However, sclerotherapy is not one single treatment.
The term includes several different techniques, including liquid sclerotherapy, ultrasound-guided foam sclerotherapy, catheter-directed foam treatment and commercially prepared polidocanol endovenous microfoam.
These methods use a sclerosant medication to deliberately injure the inner lining of an abnormal vein. The treated vein contracts, closes and is gradually converted into fibrous tissue. In foam treatment, the sclerosant is mixed with gas so that it can displace blood within the vein and maintain greater contact with the venous wall.
The important question is therefore not simply:
“Can these veins be injected?”
It is:
“Which veins are abnormal, where is the reflux coming from, and is sclerotherapy the right way to treat that particular part of the venous system?”
Current vascular guidelines recommend ultrasound-guided sclerotherapy for symptomatic varicose tributaries and recognise both physician-compounded foam and commercially prepared polidocanol endovenous microfoam as treatment options.
Why Sclerotherapy Should Still Begin With Venous Mapping
Sclerotherapy may appear simpler than laser or radiofrequency ablation because there is no thermal catheter delivering heat along the vein.
That does not make diagnosis less important.
A large visible varicose vein on the calf may be an isolated tributary suitable for direct treatment. But it may also be receiving continuous reflux from an incompetent great saphenous vein, small saphenous vein or accessory vein.
If the underlying reflux is clinically important, repeatedly injecting only the visible branches may improve their appearance without fully addressing the venous pathway feeding them.
This is why duplex Doppler ultrasound remains central to treatment planning whenever clinically significant varicose veins or venous insufficiency are suspected.
The scan helps determine whether reflux is truncal or confined to tributaries, whether recurrent veins have developed after previous treatment, and whether another type of intervention should form part of the treatment plan. Current SVS/AVF/AVLS recommendations specifically support ultrasound-guided sclerotherapy for symptomatic tributaries and combined treatment when tributaries coexist with truncal reflux.
Liquid Sclerotherapy
Liquid sclerotherapy is the traditional form of the treatment.
A sclerosant is injected directly into an abnormal superficial vein. The medication damages the venous endothelium, initiating closure and subsequent fibrosis of the treated vessel.
Liquid sclerotherapy is particularly useful for smaller reticular veins and telangiectasias, commonly known as spider veins.
These are not necessarily the same clinical problem as large symptomatic varicose veins associated with truncal venous reflux.
A patient presenting predominantly with small cosmetic surface veins may therefore require a very different treatment strategy from someone with large bulging varicosities, ankle swelling and documented great saphenous reflux.
For this reason, the size and appearance of a vein help guide treatment, but they should be considered alongside the underlying venous anatomy.
What Is Foam Sclerotherapy?
Foam sclerotherapy converts the liquid sclerosant into a foam before injection.
The foam contains a much larger surface area than the same amount of liquid medication and temporarily displaces blood from the treated segment. This allows more direct contact between the sclerosant and the vein wall.
Foam can therefore be useful in veins that are larger than those typically treated with cosmetic liquid injections.
Ultrasound-guided foam sclerotherapy (UGFS) allows the physician to see the target vein, confirm needle placement and monitor the distribution of foam during treatment.
NICE recognises ultrasound-guided foam sclerotherapy as an established interventional procedure for varicose veins and places it within the treatment pathway for confirmed truncal reflux when endothermal ablation is unsuitable.
More recent 2025 SCAI guidance also suggests foam sclerotherapy for symptomatic varicose veins without truncal reflux rather than conservative treatment alone, although the certainty of evidence for that recommendation is low.
This is important because foam has not become an obsolete treatment simply because newer catheter technologies exist.
Its role has become more selective and anatomy-driven.
Physician-Compounded Foam
One common form of foam sclerotherapy is prepared by the treating physician immediately before treatment.
A liquid sclerosant, most commonly an agent such as polidocanol or sodium tetradecyl sulfate depending on local practice, is mixed with gas to produce foam.
This is often referred to as physician-compounded foam, or PCF.
The physician selects the sclerosant concentration and volume according to the type and size of vein being treated and follows applicable clinical standards for preparation and administration.
Physician-compounded foam remains specifically recognised in current American venous guidelines as an option for ultrasound-guided treatment of symptomatic varicose tributaries.
Its flexibility is one reason it remains widely relevant in venous practice.
Polidocanol Endovenous Microfoam
Patients may increasingly encounter another term:
Polidocanol Endovenous Microfoam, or PEM.
In the United States, Varithena is an FDA-approved, commercially manufactured polidocanol injectable microfoam.
It is different from manually prepared physician-compounded foam because the foam is manufactured to have controlled characteristics, including its gas composition and bubble size.
The FDA-approved indication includes treatment of incompetent great saphenous veins, accessory saphenous veins and visible varicosities associated with the GSV system above and below the knee.
Its mechanism is still sclerotherapy: the foam displaces blood and polidocanol acts on the venous endothelium, leading to occlusion and eventual replacement of the treated vein by fibrous tissue.
PEM has accumulated a larger evidence base over recent years. A recent living network meta-analysis reported vein-closure outcomes comparable with endovenous thermal ablation in the evidence evaluated, without evidence of increased DVT risk through follow-up extending to six years.
That does not mean microfoam should replace EVLA or RFA for every patient.
It means commercially prepared microfoam has become a genuine contemporary treatment option rather than simply a cosmetic injection technique.
Physician-Compounded Foam and Microfoam Are Not Exactly the Same Thing
The words “foam sclerotherapy” are sometimes used as though every foam product and preparation were identical.
They are not.
Physician-compounded foam is produced at the time of treatment, whereas commercially prepared polidocanol endovenous microfoam is manufactured using a controlled system.
These differences can affect bubble characteristics, gas composition, dosing and the published evidence associated with the individual treatment.
Current guidelines therefore deliberately distinguish physician-compounded foam (PCF) from polidocanol endovenous microfoam (PEM) rather than treating them as interchangeable names.
Research comparing these approaches is still developing. A 2026 study specifically compared Varithena with physician-compounded foam for truncal varicose veins, illustrating that this remains an active area of investigation rather than a completely settled question.
For patients, the practical lesson is simple:
If a clinic recommends “foam,” it is reasonable to ask which sclerosant and which type of foam will actually be used.
Catheter-Directed Foam Sclerotherapy
Foam does not always have to be delivered through direct needle puncture into each target vein.
In catheter-directed foam sclerotherapy, a catheter is positioned inside the vein and foam is delivered along the target segment.
The aim is to achieve more controlled distribution of sclerosant within a defined venous pathway.
Catheter-directed techniques have been investigated for treatment of refluxing great saphenous veins and as an alternative or modification of conventional ultrasound-guided foam injection. Clinical studies and systematic review data suggest that catheter-directed delivery can achieve effective vein closure in selected patients, although it is not currently as universally established as EVLA or RFA for truncal reflux.
It should therefore be described as a technique within sclerotherapy, not as a completely separate disease treatment.
When Is Foam Sclerotherapy Particularly Useful?
One major advantage of foam is its ability to reach veins that may be difficult to treat with a straight thermal catheter.
Varicose tributaries can be extremely tortuous.
Recurrent veins after previous surgery or ablation may form irregular networks rather than one simple straight vessel.
In these situations, inserting a laser or radiofrequency catheter through the entire abnormal pathway may be technically difficult or unnecessary.
Ultrasound-guided foam can sometimes be introduced directly into the relevant veins and distributed through the target network.
This makes it particularly useful in selected cases of tortuous tributaries, recurrent varicose veins and residual veins after previous treatment, while guidelines also recognise it as an adjunct to treatment of associated varicosities after or alongside truncal ablation.
Foam Sclerotherapy and Recurrent Varicose Veins
Recurrent varicose veins are often more complicated than untreated primary disease.
A patient may previously have undergone stripping, EVLA, RFA, glue treatment, phlebectomy or sclerotherapy.
Years later, new visible veins may develop.
The cause may be reopening of a previously treated vein, reflux through an accessory vein, residual tributaries, progression of venous disease or development of a new reflux pathway.
Foam sclerotherapy can be particularly useful in selected recurrent veins because it does not always require a long straight segment suitable for a thermal catheter.
But recurrence should still be remapped before treatment.
The appropriate question is not:
“Can we inject these veins again?”
It is:
“Where is the recurrent reflux coming from now?”
Can Foam Be Combined With EVLA or RFA?
Yes.
Combination treatment is common in modern venous practice because different veins in the same leg may require different techniques.
For example, Doppler may show an incompetent great saphenous vein together with multiple large varicose tributaries.
The main truncal vein may be treated with EVLA or RFA while associated tributaries are treated with ultrasound-guided foam sclerotherapy.
Current venous guidelines specifically recommend ablation of a refluxing trunk with concomitant phlebectomy or ultrasound-guided foam sclerotherapy for associated varicosities in appropriate patients.
This highlights an important principle:
Sclerotherapy does not have to compete with thermal ablation. The methods can treat different components of the same venous disease.
Is Foam Sclerotherapy Less Effective Than Laser?
The answer depends on what is being treated.
For straightforward symptomatic truncal reflux, EVLA or RFA may offer a more durable anatomical strategy in many patients, and NICE continues to position endothermal ablation before ultrasound-guided foam when endothermal treatment is suitable.
However, comparing “foam versus laser” without specifying the anatomy can be misleading.
Foam may be particularly well suited to tributaries and tortuous recurrent veins that would not be ideal targets for a thermal catheter.
Commercial polidocanol microfoam has also produced increasingly competitive outcomes in studies of truncal venous incompetence.
Treatment selection should therefore consider anatomy, expected durability, symptoms, previous treatment and patient-specific risks, rather than assuming one technology is always superior.
Why Several Sclerotherapy Sessions May Be Needed
Sclerotherapy does not always produce complete treatment in one session.
The number of veins, size of the treatment area and maximum amount of sclerosant that can safely be administered can limit how much treatment is performed at once.
Some veins may close completely after the first treatment while others remain partially patent or become visible only after larger veins have resolved.
Commercial microfoam also has defined dosing limits. For example, current FDA prescribing information for Varithena specifies maximum volumes per injection and per treatment session and allows additional sessions when required.
Therefore, requiring a second session does not automatically mean the first treatment failed.
In appropriately planned sclerotherapy, staging may be part of the treatment strategy from the beginning.
What Happens After Sclerotherapy?
After treatment, the vein undergoes an inflammatory and fibrotic response.
The treated vein may temporarily feel firm, tender or cord-like.
Visible veins usually do not disappear immediately.
The body gradually remodels the treated vein over time, and cosmetic improvement can continue for weeks or months.
In some patients, small areas of trapped blood or retained coagulum can remain within treated veins. These can occasionally be aspirated during follow-up if clinically appropriate. The FDA prescribing information for polidocanol microfoam specifically notes that retained coagulum can be removed to improve comfort and reduce staining.
Patients should therefore understand that the procedure date and the final cosmetic result are not the same point in time.
Hyperpigmentation After Sclerotherapy
One of the best-known cosmetic side effects of sclerotherapy is hyperpigmentation, meaning brown or darker discoloration along the path of a treated vein.
Pigmentation can occur when blood products and inflammatory changes remain in or around the treated vein during healing.
In many patients it gradually fades, but it can sometimes persist for a prolonged period.
This matters especially when treatment is being performed primarily for cosmetic reasons.
Hyperpigmentation remains sufficiently relevant that a 2026 randomized controlled trial of polidocanol foam specifically evaluated treatment modifications intended to reduce this complication while maintaining vein closure.
A patient should therefore not be promised perfectly clear skin immediately after treatment.
Other Possible Side Effects and Complications
Sclerotherapy is minimally invasive, but it is still a medical intervention.
Temporary pain, tenderness, bruising, local inflammation and superficial thrombophlebitis can occur.
Extravasation, meaning sclerosant entering tissue outside the intended vein, can also cause local injury.
Venous thrombosis is an important though less common complication.
For FDA-approved polidocanol microfoam, reported treatment-related adverse events in clinical trials included limb discomfort, injection-site problems, superficial thrombophlebitis and venous thrombosis. The prescribing information also warns about severe allergic reactions, tissue injury after incorrect arterial administration and thrombotic complications.
This is why sclerotherapy should not be treated as though it were simply a cosmetic beauty injection.
The physician needs to know the anatomy, use an appropriate sclerosant and dose, and recognise patients with increased risk.
Thrombosis Risk Matters Before Treatment
A history of deep vein thrombosis or pulmonary embolism, reduced mobility, recent major surgery and other thrombotic risk factors can change treatment planning.
Active thromboembolic disease is a contraindication to FDA-approved polidocanol microfoam. Its prescribing information also highlights increased concern in patients with reduced mobility or previous DVT or PE.
This does not mean every patient with a remote history of thrombosis can never undergo any form of sclerotherapy.
It means the specialist must understand the history and assess the risks before treatment.
For an international patient, this history should be communicated before travel whenever possible, particularly if long-distance flying is also involved.
Sclerotherapy for Spider Veins Is Different From Treatment for Venous Insufficiency
This distinction deserves its own section because patients frequently use the same word—“sclerotherapy”—for very different treatments.
A patient with a few isolated spider veins may receive small-volume cosmetic liquid sclerotherapy.
Another patient may have extensive great saphenous reflux, painful varicose tributaries and edema and undergo ultrasound-guided microfoam treatment as part of treatment for chronic venous disease.
Both procedures may technically be called sclerotherapy.
Their diagnosis, treatment planning, risk assessment and follow-up are not the same.
A credible medical plan should therefore distinguish cosmetic surface-vein treatment from treatment of clinically significant venous reflux.
Sclerotherapy Abroad: Why the Diagnosis Should Be Clear Before Travel
For patients considering sclerotherapy for varicose veins abroad, photographs can be useful for preliminary review.
They can show whether veins appear small, reticular, tortuous or prominently varicose.
But photographs cannot show whether the veins are connected to underlying truncal reflux.
Whenever larger or symptomatic varicose veins are present, available Doppler studies, previous treatment reports and thrombosis history should be reviewed before the final procedure is selected.
If a current venous Doppler is not available, the final treatment plan may appropriately be confirmed after examination and ultrasound mapping in Türkiye.
This is particularly important because the patient may initially request “foam injections” but ultimately require a different or combined approach.
What International Patients Should Ask Before Sclerotherapy
Patients travelling for sclerotherapy should know what type of vein is being treated and what type of sclerotherapy is planned.
They should understand whether the plan involves liquid sclerosant, physician-compounded foam, commercial polidocanol microfoam or another technique.
They should also clarify whether the treatment is directed at isolated tributaries or a refluxing truncal vein, whether multiple sessions are expected, whether another procedure such as EVLA, RFA or phlebectomy is also recommended, and what follow-up is needed before travelling home.
A clear discharge record becomes particularly valuable if further treatment is needed later.
Healing Journey’s broader treatment-abroad model also emphasises that patients should return home with treatment details and a defined follow-up pathway rather than losing continuity once the procedure has been completed. This is consistent with the existing HJ approach of arranging treatment around follow-up capability and documenting what was performed before the patient returns home.
What Patients Should Not Assume About Sclerotherapy
Patients should not assume that every visible vein can be treated effectively with the same injection.
They should not assume that foam is only a cosmetic treatment.
They should not assume that microfoam and manually compounded foam are identical.
They should not assume that a newer commercially prepared product is automatically superior for every anatomy.
And they should not assume that repeatedly injecting visible veins will solve significant underlying reflux if the source has not been assessed.
Sclerotherapy is most useful when it is treated as part of venous disease management, rather than simply as a way of making visible veins disappear.
Why is Doppler mapping important before foam sclerotherapy?
Doppler helps determine whether the visible veins are isolated tributaries or are being supplied by a deeper superficial reflux pathway. This can change whether sclerotherapy alone, truncal ablation, or a combination of treatments is most appropriate.
What should patients know before arranging sclerotherapy abroad?
Patients should know which veins are being treated, whether liquid, physician-compounded foam or commercial microfoam is planned, whether several sessions or combination treatment may be needed, what risks and recovery advice apply, and how follow-up will continue after they return home.
Selected References
- Society for Vascular Surgery, American Venous Forum and American Vein and Lymphatic Society. Clinical Practice Guidelines for the Management of Varicose Veins of the Lower Extremities.
- Society for Cardiovascular Angiography & Interventions. 2025 SCAI Clinical Practice Guidelines for the Management of Chronic Venous Disease.
- National Institute for Health and Care Excellence. Ultrasound-Guided Foam Sclerotherapy for Varicose Veins and Varicose Veins: Diagnosis and Management.
- U.S. Food and Drug Administration. Varithena (Polidocanol Injectable Foam) Prescribing Information.
- Contemporary evidence evaluating polidocanol endovenous microfoam, physician-compounded foam and evolving foam techniques continues to refine where these approaches fit within modern varicose vein treatment.
