Sclerotherapy
About Sclerotherapy
Sclerotherapy is a medical treatment for thread veins, the fine red, blue or purple veins that show through the skin, in which a solution is injected into each vein through a very fine needle so that it closes and gradually fades. When it is used for the smallest veins it is often called microsclerotherapy. It is most commonly used on the legs and suits adults in good general health who would like clearer looking skin, whatever their skin tone. The solution, known as a sclerosant, is a prescription medicine in many countries, so treatment is carried out by doctors and nurses trained in vein care, or under the direct oversight of a prescriber where local rules allow. A session is usually under an hour and feels like a series of small pricks, sometimes with brief stinging or cramping. Most people walk out and carry on with their day, though compression stockings are often worn for a few days afterwards. Veins can look darker before they fade; improvement often starts after a few weeks, with the main result at around three months. Many people need two to six sessions. Treated veins do not return, but new ones can appear over time.
On the day, and after
During the treatment
A session is usually under an hour, and its length depends on how many veins are treated. You lie on a treatment couch with your legs exposed, and your practitioner cleanses the skin. Photographs are often taken so progress can be compared over time. Some practitioners use magnification or a special light to see the veins more clearly.
Using a very fine needle, your practitioner injects a small amount of sclerosant into each vein. You may see the vein briefly clear as the solution travels along it. The two licensed sclerosants most widely used are polidocanol and sodium tetradecyl sulfate, which irritate the vein lining so the vessel seals and is gradually absorbed by the body. Cotton pads or tape may be placed over the injection points, and compression stockings are put on before you stand. Most clinics then suggest a short walk. You will be given written care instructions and details of your next session, usually around four weeks later.
How it feels
Most people find sclerotherapy very manageable. The needle is extremely fine, so each injection feels like a small prick. As the solution enters the vein, some people notice a brief stinging, burning or cramping feeling, which usually fades within seconds to a minute. Stronger solutions used for slightly larger veins can feel more noticeable.
Straight after treatment, the treated areas may look raised and red, rather like a nettle rash, and feel itchy for a few hours. Compression stockings feel snug but should not be painful or leave your toes cold or numb.
Over the following days, the legs may feel a little tender or bruised. Firm, slightly sore spots can develop along treated veins and soften over the coming weeks. Pain that grows rather than eases is not expected and should be checked by your clinic.
Results and maintenance
Results build gradually. Treated veins often begin to fade about three weeks after a session, with the main benefit seen at around three months, and improvement can continue for up to a year. Many people need two to six sessions, usually spaced about four weeks apart, and a course often brings a significant improvement in how the legs look.
Treated veins close permanently, but sclerotherapy does not stop new thread veins from forming. Genetics, hormones, pregnancy and long periods of standing all play a part, so many people book an occasional top up session every year or two.
To help keep your legs looking clear:
- Stay active and walk regularly to support circulation.
- Raise your legs when resting, and avoid long periods standing still.
- Consider compression hosiery during long journeys or days on your feet.
- Protect your legs from the sun.
Before and after your appointment
Before your appointment
Treatment starts with a consultation. Your practitioner will examine your legs, ask about your health, any leg symptoms such as aching, swelling or itching, and your family history of vein problems. If there are signs of deeper vein disease, they may arrange an ultrasound scan, since treating the underlying cause comes first. You should have time to consider the plan before you agree to treatment.
Before your appointment:
- Bring a list of all your medicines and supplements, including the contraceptive pill or hormone therapy.
- Avoid fake tan and moisturiser on your legs on the day.
- Do not shave or wax your legs for a day or two beforehand.
- Wear loose trousers or a skirt so stockings can go on easily afterwards.
- Bring or buy the compression stockings your clinic recommends.
- Plan a short walk after treatment, and avoid booking right before a long flight.
Aftercare
Good aftercare helps the treated veins close well and reduces the chance of staining. Your clinic will give you its own instructions, and following them closely is the best plan.
Common advice includes:
- Wear your compression stockings as directed, often day and night at first and then during the day for a week or more.
- Walk regularly, aiming for a few short walks each day, and avoid standing still for long periods.
- Raise your legs when resting for the first few days.
- Avoid hot baths, saunas, hot tubs and strenuous exercise for several days.
- Protect treated areas from the sun and tanning beds until any marks have faded.
- Check with your practitioner before long flights in the weeks after treatment.
Contact your clinic promptly if you notice a painful, hot or swollen leg, a red streak along a vein, a sore that will not heal at an injection site, or any signs of an allergic reaction.
There is very little downtime, and most people return to work and normal activity the same day. Walking is encouraged, while heavy exercise, hot baths and saunas are best avoided for several days.
The treated veins usually look worse before they look better. Bruising, redness and slight swelling are common and settle over days to a few weeks, though bruising can occasionally last longer. Some people notice:
- Brown staining along treated veins, which usually fades over weeks to months
- A cluster of very fine new red vessels near the treated area, known as matting, which often settles over months
- Small firm lumps or raised patches along treated veins, which usually settle over time
Rarely, a small skin ulcer can form at an injection site. Report any wound that does not heal, or any painful swelling, to your clinic straight away.
Safety and medical considerations
Safety essentials
Sclerosants are prescription medicines in the UK, the US and Australia, among many other countries. That means a prescriber, such as a doctor or nurse prescriber, must assess you and decide treatment is suitable. In the US, polidocanol is FDA approved as Asclera for spider and reticular veins; in Australia, sodium tetradecyl sulfate is a prescription only medicine. Rules on who may inject differ by country, but good practice is treatment by doctors or nurses trained in vein care, or by a practitioner working under the direct oversight of a prescriber who has assessed you. In the UK, vein specialists have raised concerns about complications after treatment by untrained practitioners without medical supervision.
Good practice includes:
- A face to face assessment before treatment, with a scan if there are signs of deeper vein disease
- Licensed products from a regulated supplier, with batch details recorded
- The lowest effective strength and volume of solution
- Sterile, single use needles and a clean clinical room
- Written consent, aftercare and follow up
Medical considerations
Sclerotherapy is not usually offered during pregnancy or breastfeeding. Veins that appear during pregnancy can change afterwards, so your practitioner may suggest waiting a while after the birth before deciding on treatment. Your practitioner will also check carefully, and may advise against treatment, if you have:
- A history of blood clots, deep vein thrombosis or a clotting disorder
- Reduced mobility or will be unable to walk after treatment
- Poor circulation in the legs or leg ulcers
- A known allergy to a sclerosant
- An infection or skin condition in the treatment area
- Symptoms of deeper vein disease, such as aching, swelling or varicose veins
Hormonal medicines, including some contraceptive pills and hormone therapy, can affect clotting risk, so mention these. If you have leg pain, swelling, skin changes or new veins appearing quickly, see your GP first, as these may need investigation before any cosmetic treatment.
Patch testing
A traditional skin patch test is not usually needed for sclerotherapy. Allergic reactions to modern sclerosants are uncommon and usually mild, such as hives, while severe reactions are very rare.
Instead, your practitioner will take a full medical history and ask about allergies to medicines, any previous reactions to sclerotherapy and your general health. Some practitioners choose to treat a small test area at the first visit, especially if you have sensitive skin or are concerned about staining. This lets you both see how your skin responds before a larger area is treated, and it is a clinical decision made case by case.
A good clinic has emergency medicines and trained staff on hand in case of an allergic reaction, and will ask you to stay for a short while after your first treatment so you can be observed.
Knowing a good practitioner
Green flags
A well run vein clinic puts careful assessment first. Look for:
- A doctor or nurse trained in vein care, registered with a professional regulator
- A thorough consultation that covers your health, symptoms and family history
- An ultrasound scan where there are signs of deeper vein problems
- A clear explanation of the solution being used and how it works
- Honest expectations about the number of sessions, temporary darkening and new veins in future
- Before and after photographs taken in the same lighting
- Compression stockings fitted and walking advice given
- A review appointment and a named contact for any concerns
Clinics that offer both sclerotherapy and laser can recommend the best option for your skin tone and vein size, and sclerotherapy is often preferred over laser for deeper skin tones.
Red flags
Look elsewhere if you notice any of these:
- No assessment by a prescriber, or a prescription arranged without seeing you
- No questions about blood clots, pregnancy, medication or leg symptoms
- Larger varicose veins injected with no scan or specialist assessment
- Unlabelled solutions or products without batch details
- Treatment offered in a home, at an event or in a room that is not clinically clean
- No compression stockings or walking advice afterwards
- Promises of instant or permanent results after a single session
- No written aftercare and no route to contact the clinic later
After treatment, seek urgent medical help if you develop a swollen, painful or hot calf, sudden breathlessness or chest pain, or changes to your vision or speech. These are rare, but they need immediate attention.
Questions to ask
These questions help you choose a skilled, safe practitioner:
- What are your qualifications in treating veins, and who prescribes the solution?
- Do I need an ultrasound scan before treatment?
- Which sclerosant will you use, and at what strength?
- How many sessions are likely, and how far apart?
- How long will I need to wear compression stockings?
- What side effects should I expect, and how are they managed?
- When will you review my results?
Frequently asked questions
Does sclerotherapy hurt?
Most people find it very manageable. The needle is extremely fine, so each injection feels like a small prick, sometimes with a brief sting or cramp as the solution goes in. Treated areas may itch and look raised for a few hours, then feel slightly tender for a few days.
How many sclerotherapy sessions will I need?
Many people need two to six sessions, usually spaced around four weeks apart. The number depends on how many veins you have, their size and how your skin responds. Your practitioner will review your progress at each visit and adjust the plan.
How long does it take to see results from sclerotherapy?
Veins often look darker at first, then begin to fade after about three weeks. The main improvement is usually visible around three months after treatment, and results can continue improving for up to a year. Patience is part of the process, as the body absorbs the treated veins gradually.
Who can perform sclerotherapy?
The solution used is a prescription medicine in many countries, including the UK, the US and Australia, so a prescriber must assess you first. Good practice is treatment by a doctor or nurse trained in vein care, or by a practitioner under a prescriber's direct oversight where rules allow.
Do thread veins come back after sclerotherapy?
Treated veins close permanently, but new thread veins can form over time because of genetics, hormones, pregnancy or long periods of standing. Many people choose an occasional top up session to treat new veins as they appear. Staying active and raising your legs when resting can help.
How long do I wear compression stockings after sclerotherapy?
It varies by clinic and by the size of veins treated. Many practitioners advise wearing them for several days to around two weeks, sometimes day and night at first. Compression helps the veins close well and may reduce the risk of brown staining. Follow your own clinic's advice.
This guide is general information, not medical advice. Speak to a qualified practitioner, and to your GP if you have a medical condition, before booking.