Thread veins are incredibly common — and yet they’re often misunderstood. For some people, they’re a minor cosmetic nuisance. For others, they can affect confidence, clothing choices, and how comfortable they feel in their own skin.
At Doghurst Clinic, we regularly see patients who’ve been told their thread veins are “just cosmetic”, have tried creams or laser treatments without success, or feel unsure whether treatment is worth pursuing at all. What most people want is not perfection — but clear, honest information about what causes thread veins, what genuinely helps, and what results are realistic.
Microsclerotherapy is widely recognised as the gold-standard treatment for thread veins on the legs, when used appropriately and following proper assessment. This article explains how and why thread veins develop, what influences them, how microsclerotherapy works, and what to expect — all in line with guidance from the British Association of Sclerotherapists and the National Institute for Health and Care Excellence.
Why do thread veins develop?
Thread veins form when very small superficial veins become dilated and visible beneath the skin. In most cases, this happens gradually and for more than one reason.
Genetics play the biggest role — if close family members have thread veins, you’re far more likely to develop them yourself. Hormonal influences are also significant, particularly during pregnancy, menopause, or with the use of oral contraception or HRT. Over time, natural ageing affects the elasticity of blood vessels, making them more prone to dilating.
In the legs, gravity matters. Prolonged standing or sitting increases pressure within the venous system, and if the deeper veins aren’t working as efficiently as they should, that pressure can be transmitted to smaller surface veins. This is why thread veins often appear or worsen over time, rather than suddenly.
Importantly, thread veins are not caused by poor circulation, and they are rarely dangerous. However, they do reflect changes within the superficial venous system — and once visible, they do not disappear on their own.
What tends to worsen thread veins — and what helps?
Thread veins often become more noticeable during periods of hormonal change, pregnancy, weight gain, or prolonged standing. Heat — including hot baths, saunas, and sun exposure — can temporarily dilate veins, making them appear more prominent.
Regular movement, walking, maintaining a healthy weight, and avoiding long periods of static standing can help slow progression. Compression hosiery can also be useful for some people, particularly if symptoms worsen at the end of the day.
That said, it’s important to be realistic: lifestyle measures can help reduce progression, but they do not remove established thread veins. Once veins are visible, medical treatment is required to treat them.
Choosing the right treatment for thread veins
There are many treatments marketed for thread veins, but effectiveness depends on vein type and location.
Laser, diathermy and IPL treatments can be helpful for very fine facial veins, but they are generally less effective for leg thread veins, which tend to sit deeper and are influenced by venous pressure. For this reason, microsclerotherapy remains the treatment of choice for most leg thread veins.NICE guidance is clear that significant venous reflux should be identified and managed before cosmetic treatment, as treating surface veins alone may lead to poor or short-lived results.
What is microsclerotherapy?
Microsclerotherapy is a medical injection treatment used to treat small superficial veins on the legs. Using an extremely fine needle, a sclerosant solution is injected directly into the affected vein.
The sclerosants most commonly used in the UK are polidocanol and sodium tetradecyl sulphate (STS). These agents have been used safely for decades and are supported by robust clinical evidence.
The sclerosant irritates the lining of the vein in a controlled way, causing it to spasm, collapse, and seal. Over the following weeks and months, the body gradually breaks the treated vein down and reabsorbs it. Once treated successfully, the vein cannot reopen.
Why does treatment sometimes need more than one session?
Thread veins rarely exist as single, isolated veins. They tend to form networks, with multiple small vessels feeding into one another. When one vein is treated, blood flow redistributes, sometimes revealing veins that were not previously visible.
For this reason, microsclerotherapy is best approached as a course of treatment, rather than a one-off procedure. Most people require two to four sessions, spaced several weeks apart, to achieve the best cosmetic outcome.
Hormonal influences, skin type, vein size, and compression use after treatment all affect results — which is why careful assessment and expectation-setting are essential.
What improves outcomes?
Results are optimised when treatment is planned properly and aftercare is followed. Wearing compression stockings after treatment, staying active with regular walking, avoiding excessive heat, and allowing sufficient time between sessions all improve outcomes.
Microsclerotherapy works gradually. Improvement is not immediate — and that’s a good thing. Slow, controlled resolution reduces the risk of complications and gives the best long-term results.
Which veins are suitable — and which are not?
Microsclerotherapy is suitable for thread veins and small reticular veins on the legs. It is not appropriate for large varicose veins or veins caused by significant venous reflux, which require further assessment and treatment in line with NICE CG168.
This distinction matters. Treating the wrong veins with the wrong approach leads to disappointment — and avoidable risk.
👉 Read: Leg Vein Assessment
Risks, recovery and expected results
Microsclerotherapy is a well-established and safe procedure when performed by a trained clinician. Temporary redness, mild swelling, bruising, itching, or tenderness are common and usually settle within days to weeks. Some people experience temporary pigmentation or fine “matting” of new vessels, which typically fades over time.
Most people begin to see improvement within a few weeks, with continued fading over three to four months.
Who may not be suitable?
Microsclerotherapy is not suitable during pregnancy or breastfeeding. It may not be appropriate for people with a history of deep vein thrombosis, clotting disorders, or known allergy to sclerosants. A medical consultation is essential to ensure treatment is safe and appropriate.
In summary
Microsclerotherapy remains the gold-standard, evidence-based treatment for leg thread veins — but good results rely on proper assessment, realistic expectations, and appropriate aftercare. It is not about perfection; it is about achieving natural, progressive improvement in a safe, medically sound way.At Doghurst Clinic, microsclerotherapy is delivered as part of a doctor-led vein service, following BAS and NICE guidance, with careful attention to safety, technique, and long-term outcomes.
Book a Microsclerotherapy Consultation at Doghurst Clinic
Frequently Asked Questions
Is microsclerotherapy painful?
Most people describe mild stinging during injections, which settles quickly. It can sometimes be itchy for a short while afterwards.
How many treatments will I need?
Most patients require two to four sessions for optimal results.
Will thread veins come back?
Treated veins do not return, but new veins may develop over time.
Can I walk after treatment?
Yes — walking is encouraged immediately.
Do I need compression stockings?
Yes. Compression improves outcomes and is recommended by BAS. Compression hose must be worn for at least 7 days after treatment.
Evidence and guidance
- British Association of Sclerotherapists – Sclerotherapy guidelines
- National Institute for Health and Care Excellence CG168: Varicose veins in the legs
- Goldman MP. Sclerotherapy: Treatment of Varicose and Telangiectatic Leg Veins
Related service: Find out more about sclerotherapy for thread veins at Doghurst Clinic, including assessment, suitability and what to expect from treatment.