What Is Sclerotherapy? How Spider Vein Injections Work
Sclerotherapy is an injection treatment used to close unwanted superficial veins. This guide explains how it works, the difference between sclerotherapy and microsclerotherapy, which veins may be suitable, what recovery involves and the important limitations to understand.
Sclerotherapy is a minimally invasive procedure in which a sclerosing solution is injected into a suitable vein. The solution affects the inner lining of the vein, causing it to close. Over time, the treated vessel becomes less visible as the body gradually deals with the closed vein. Microsclerotherapy applies this principle to small superficial spider and thread veins.
What Is Sclerotherapy?
Sclerotherapy is a treatment used for certain unwanted or abnormal veins. Rather than surgically removing the vessel, a practitioner injects a sclerosant into the vein.
The sclerosant affects the inner lining of the treated vessel and encourages it to close. The closed vessel can then become progressively less noticeable over time.
The term sclerotherapy covers more than one type of vein treatment. The technique, sclerosant concentration and method used depend on the type and size of vein being treated.
How Does Sclerotherapy Work?
A fine needle is used to introduce a small amount of sclerosant into the targeted vessel. The sclerosant acts on the vein lining, initiating a process that closes the treated vessel.
This does not mean that the vein disappears immediately. The appearance normally changes gradually as the treated vessel responds and becomes less visible.
Several small veins may be treated during one appointment, depending on their distribution, size, the treatment area and individual suitability.
What Is Microsclerotherapy?
Microsclerotherapy is a form of sclerotherapy used for small, superficial veins. It is particularly associated with treating spider veins and thread veins on the legs.
The word “micro” refers to the fine injection technique used for these small vessels. This is different from specialist treatment of larger varicose veins, where assessment and treatment may involve ultrasound and other vascular procedures.
At Belle Clinic, microsclerotherapy is used for suitable cosmetic leg veins following assessment. You can see the clinic's dedicated spider and thread vein treatment information for treatment suitability, current prices and booking information.
Which Veins May Be Suitable for Microsclerotherapy?
Suitability depends on the appearance, size and location of the vessel as well as your medical history. The treatment may be considered for suitable:
- Spider veins on the legs
- Thread veins on the legs
- Small visible blue, red or purple superficial leg veins
- Clusters of small superficial vessels on the thighs or lower legs
What about varicose veins?
It is important not to use “spider veins” and “varicose veins” interchangeably. Varicose veins are generally larger and may be raised, twisted or associated with symptoms.
Sclerotherapy can also be used in specialist vascular medicine for selected varicose veins — for example, ultrasound-guided foam sclerotherapy. However, this is different from cosmetic microsclerotherapy for small superficial vessels.
What Happens During a Microsclerotherapy Appointment?
Before treatment, the visible vessels and relevant medical history should be assessed to determine whether microsclerotherapy is appropriate.
During treatment, a fine needle is positioned in the selected superficial vessel and a small amount of sclerosant is administered. More than one injection may be required when several vessels or vein branches are being treated.
Appointments may take approximately 30–45 minutes depending on the number and extent of the vessels being treated.
What Is Fibrovein?
Belle Clinic uses Fibrovein for suitable microsclerotherapy treatments. Fibrovein contains sodium tetradecyl sulfate, which is a sclerosing agent used to close treated veins.
Fibrovein is a prescription-only medicine in the UK and is available in different concentrations. The appropriate product and concentration depend on the vessel and clinical circumstances.
Because sclerosants are medicines rather than cosmetic skincare products, appropriate assessment, correct technique and consideration of contraindications and risks are important.
How Long Does Sclerotherapy Take to Work?
Sclerotherapy is not an instant vein-erasing procedure. The injected vessel needs time to respond to treatment and become less noticeable.
Small veins may gradually improve over a number of weeks. Some vessels take longer, and not every visible vessel responds in exactly the same way.
More than one treatment session can sometimes be required, particularly where there are multiple clusters of veins or where some vessels remain visible after the first treatment.
What Is Recovery Like After Sclerotherapy?
Most cosmetic microsclerotherapy does not require the type of prolonged recovery associated with surgery, but the treated area can look worse before it looks better.
Temporary bruising, redness, local swelling or darker-looking vessels can occur after injections. The treated veins then need time to settle.
Compression and aftercare
Compression stockings may form part of the aftercare plan depending on the treatment and practitioner instructions. Follow the specific aftercare advice provided for your procedure rather than relying on a generic online schedule.
Aftercare may also include advice about:
- regular gentle walking and normal movement
- when to resume strenuous exercise
- heat exposure such as hot baths or saunas
- looking after the injection sites
- sun exposure where temporary pigmentation is present
- when a follow-up assessment is appropriate
If you take medicines that affect bleeding or clotting, do not stop prescribed medication simply because you are planning cosmetic treatment. Discuss medicines and relevant medical history during your assessment and follow advice from the clinician who prescribed them.
Possible Side Effects and Risks
Sclerotherapy is minimally invasive, but that does not mean it is risk-free. Expected reactions and potential complications should be discussed before treatment.
Possible reactions can include:
- temporary redness or swelling around injection sites
- bruising
- temporary tenderness, irritation or itching
- brown pigmentation along a treated vessel
- small areas of trapped blood within treated vessels
- new very fine visible vessels in the treated area
Less common but potentially more significant complications can occur, including allergic reactions, skin injury or ulceration and thrombotic complications. This is one reason suitability assessment, medical history and appropriate treatment technique matter.
Anyone experiencing an unexpected or concerning reaction after treatment should seek appropriate medical advice rather than relying solely on information from a website.
Sclerotherapy vs Laser: Which Is Used for Spider Veins?
There is no single vein-removal method that is automatically best for every visible vessel. The location, diameter, colour and depth of the vein can influence which approach is considered.
| Factor | Microsclerotherapy | Vascular Laser |
|---|---|---|
| Method | Sclerosant is injected into the vessel. | Light energy is directed towards the target vessel. |
| Common cosmetic use | Suitable superficial spider/thread veins, particularly on legs. | Can be considered for certain superficial vascular concerns depending on vessel and device. |
| Needle required? | Yes. | No injection into the vessel. |
| Choice depends on | Vein size, location, depth, colour, medical history and individual suitability. | |
Facial thread veins and leg spider veins should not automatically be approached in exactly the same way. Different vessel characteristics may make different technologies or techniques more appropriate.
You can also read about Belle Clinic's thread vein removal options for further information about visible vascular concerns.
Considering Treatment for Leg Spider Veins?
This article is intended to explain sclerotherapy rather than determine whether a particular vein is suitable for treatment. Belle Clinic in Golders Green offers assessment and microsclerotherapy for suitable superficial spider and thread veins.
The dedicated treatment page contains current treatment information, suitability guidance and pricing.
View Spider Vein Treatment
Sclerotherapy FAQs
Is sclerotherapy the same as microsclerotherapy?
Microsclerotherapy is a form of sclerotherapy designed for smaller superficial vessels. The broader term sclerotherapy can also describe other vein-treatment techniques used in different clinical settings.
Does sclerotherapy remove spider veins immediately?
No. The treated vessel closes and then changes gradually. Improvement normally develops over time rather than the vein disappearing as soon as it is injected.
Can spider veins come back after sclerotherapy?
A successfully treated vessel may become much less visible, but treatment cannot prevent every new spider vein from developing in the future. New vessels can appear separately from the veins previously treated.
How many sclerotherapy sessions will I need?
This varies. The number, size and distribution of the vessels and their response to treatment all matter. Some people may require additional sessions to address remaining vessels.
Can sclerotherapy be used for varicose veins?
Sclerotherapy can be used for selected varicose veins in specialist vascular care, including ultrasound-guided foam sclerotherapy in appropriate cases. That is different from Belle Clinic's cosmetic microsclerotherapy service for suitable superficial spider and thread veins.
Is sclerotherapy painful?
The procedure involves fine-needle injections, so brief stinging or discomfort may occur. Individual sensitivity and the number of injections required vary.
Is microsclerotherapy suitable for facial thread veins?
Treatment selection depends on the vessel and location. Facial vessels are often assessed differently from leg spider veins, and other vascular treatment methods may be considered instead.
Can everyone have sclerotherapy?
No. Medical history, medicines, allergies, vein characteristics and other individual factors can affect suitability. An appropriate assessment should take place before treatment.
About Belle Clinic
Belle Clinic is based in Golders Green, North West London. The clinic provides laser, skin and aesthetic treatments, including microsclerotherapy for suitable superficial spider and thread veins.
Treatment suitability varies, so assessment is important when the type of visible vein is uncertain or where there are larger or symptomatic vessels.
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Sources & Further Reading
Medical information in this guide has been written for general education and should not replace individual medical assessment.
Visit Belle Clinic in Golders Green
If you would like your visible leg veins assessed and want to find out whether microsclerotherapy may be appropriate, contact Belle Clinic in Golders Green, North West London.
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