Varicose veins are usually caused by weak vein walls and valves.

Inside your veins are tiny one-way valves that open to let the blood through, and then close to prevent it flowing backwards.

Sometimes the walls of the veins become stretched and lose their elasticity, causing the valves to weaken.

If the valves don't function properly, this can cause the blood to leak and flow backwards. If this happens, the blood collects in your veins, which become swollen and enlarged.

The reasons why the walls of the veins stretch and the valves in your veins weaken aren't fully understood. Some people develop the condition for no obvious or apparent reason.

Increased risk

A number of things can increase your likelihood of developing varicose veins, including:

• being female
• having a close family member with varicose veins
• older age
• being overweight
• having a job that involves long periods of standing
• being pregnant
• other conditions

Gender

Women are more likely to be affected by varicose veins than men. Research suggests this may be because female hormones tend to relax the walls of veins, making the valves more prone to leaking.

Hormones are chemicals produced by the body, and changes may be caused by pregnancy, premenstrual syndrome or the menopause.

Genetics

Your risk of developing varicose veins is increased if a close family member has the condition.

This suggests varicose veins may be partly caused by your genes (the units of genetic material you inherit from your parents).

Visit our page on genetics for more information about how you inherit your physical and behavioural characteristics.

Age

As you get older, your veins start to lose their elasticity and the valves inside them stop working as well.

Being overweight

Being overweight puts extra pressure on your veins, which means they have to work harder to send the blood back to your heart.

This can put increased pressure on the valves, making them more prone to leaking.

The impact of body weight on the development of varicose veins appears to be more significant in women.

Use the healthy weight calculator to check whether you're overweight.

Occupation

Some research suggests jobs that require long periods of standing may increase your risk of getting varicose veins.

This is because your blood doesn't flow as easily when you're standing for long periods of time.

Pregnancy

During pregnancy, the amount of blood increases to help support the developing baby. This puts extra strain on your veins.

Increased hormone levels during pregnancy also cause the muscular walls of the blood vessels to relax, which also increases your risk.

Varicose veins may also develop as the womb (uterus) begins to grow. As the womb expands it puts pressure on veins in your pelvic area, which can sometimes cause them to become varicose.

Although being pregnant can increase your risk of developing varicose veins, most women find their veins significantly improve after the baby is born.

Read more about varicose veins during pregnancy.

Other conditions

In rare cases, varicose veins are caused by other conditions.

These include:

• a previous blood clot
• a swelling or tumour in the pelvis
• abnormal blood vessels

If you have varicose veins and they don't cause you any discomfort, you may not need to visit your GP.

Varicose veins are rarely a serious condition and they don't usually require treatment.

But speak to your GP if:

• your varicose veins are causing you pain or discomfort
• the skin over your veins is sore and irritated
• the aching in your legs is causing irritation at night and disturbing your sleep

Seeing your GP

Varicose veins are diagnosed by their appearance. Your GP will examine your legs while you're standing to check for signs of swelling.

You may also be asked to describe any pain you have and whether there are situations that make your varicose veins worse.

For example, some women find their menstrual cycle (period) affects their varicose veins.

Your GP will also want to know if you're at an increased risk of developing varicose veins, such as:

• having a family history of varicose veins
• being pregnant
• whether you have a healthy body mass index (BMI)
• having deep vein thrombosis (a blood clot in one of the deep veins of the body)
• a history of leg injury (for example, having previously broken a bone in your leg)

Further investigation

Your GP may refer you to a vascular specialist (a doctor who specialises in veins) if you have any of the following:

• varicose veins that are causing pain, aching, discomfort, swelling, heaviness or itching (whether or not you've had varicose veins before)
• changes in the colour of the skin on your leg that may be caused by problems with the blood flow in the leg
• skin conditions affecting your leg, such as eczema, that may be caused by problems with the blood flow in the leg
• hard and painful varicose veins that may be caused by problems with the blood flow in the leg
• a healed or unhealed leg ulcer (a break in the skin that has not healed within 2 weeks) below the knee

In most cases, a test called a duplex ultrasound scan will be carried out. This is a type of scan that uses high-frequency sound waves to produce a picture of the veins in your legs.

The picture shows the blood flow and helps the vascular specialist locate any damaged valves that might be causing your varicose veins.

Varicose veins don't always need treatment. If your varicose veins aren't causing you discomfort, you may not need to have treatment.

Treatment of varicose veins is usually necessary:

• to ease symptoms – if your varicose veins are causing you pain or discomfort
• to treat complications – such as leg ulcers, swelling or skin discolouration
• for cosmetic reasons – but this kind of treatment is rarely available on the NHS, so you'll usually have to pay for it to be done privately

If treatment is necessary, your doctor may first recommend up to 6 months of self care at home.

This may involve: 

• using compression stockings (your blood circulation will first be checked to see if these are suitable for you)
• exercising regularly
• avoiding standing up for long periods
• elevating the affected area when resting

The various treatments for varicose veins are outlined below.

Compression stockings

Compression stockings aren't suitable for everyone. Before these can be recommended for you, you'll need to have a special test called a Doppler investigation to check your blood circulation.

Compression stockings are specially designed to steadily squeeze your legs to improve circulation. They're often tightest at the ankle and get gradually looser as they go further up your leg. This encourages blood to flow upwards towards your heart.

They may help relieve the pain, discomfort and swelling in your legs caused by your varicose veins. But it's not known whether the stockings help prevent your varicose veins getting worse, or if they prevent new varicose veins appearing.

The National Institute for Health and Care Excellence (NICE) only recommends using compression stockings as a long-term treatment for varicose veins if all other treatments aren't suitable for you.

If you're pregnant and have varicose veins, NICE says you may be offered compression stockings for the duration of your pregnancy.

Compression stockings are available in a variety of different sizes and pressures. Most people with varicose veins will be prescribed a class 1 (light compression) or class 2 (medium compression) stocking.

They are also available in:

• different colours
• different lengths – some come up to your knee, while others also cover your thigh
• different foot styles – some cover your whole foot, and some stop before your toes

Compression tights are also available, but not on the NHS. They can be bought from pharmacies or directly from the manufacturers.

You may need to wear compression stockings for the rest of your life if you have deep venous incompetence (blockages or problems with the valves in the deep veins in your legs).

In these circumstances, you'll need to wear compression stockings even if you've had surgery to treat some varicose veins.

Wearing compression stockings

You usually need to put your compression stockings on as soon as you get up in the morning and take them off when you go to bed.

They can be uncomfortable, particularly during hot weather, but it's important to wear your stockings correctly to get the most benefit from them.

Pull them all the way up so the correct level of compression is applied to each part of your leg. Don't let the stocking roll down, or it may dig into your skin in a tight band around your leg.

Speak to your GP if the stockings are uncomfortable or don't seem to fit. It may be possible to get custom-made stockings that will fit you exactly.

If custom-made compression stockings are recommended, your legs will need to be measured in several places to ensure they're the correct size.

If your legs are often swollen, they should be measured in the morning, when any swelling is likely to be minimal.

If compression stockings are causing the skin on your legs to become dry, try applying a moisturising cream (emollient) before you go to bed to keep your skin moist.

You should also keep an eye out for sore marks on your legs, as well as blisters and discolouration.

Caring for compression stockings

Compression stockings usually have to be replaced every 3 to 6 months. If your stockings become damaged, speak to your GP because they may no longer be effective.

You should be prescribed 2 stockings (or 2 sets of stockings if you're wearing 1 on each leg) so that one stocking can be worn while the other is being washed and dried.

Compression stockings should be hand washed in warm water and dried away from direct heat.

Further treatment

If your varicose veins need further treatment or they're causing complications, the type of treatment will depend on your general health and the size, position and severity of your veins.

A vascular specialist (a doctor who specialises in veins) will be able to advise you about the most suitable form of treatment for you.

Endothermal ablation

One of the first treatments offered will usually be endothermal ablation.

This involves using energy either from high-frequency radio waves (radiofrequency ablation) or lasers (endovenous laser treatment) to seal the affected veins.

These treatments are described in more detail below.

Radiofrequency ablation

Radiofrequency ablation involves heating the wall of your varicose vein using radiofrequency energy.

The vein is accessed through a small cut made just above or below the knee.

A narrow tube called a catheter is guided into the vein using an ultrasound scan. A probe is inserted into the catheter that sends out radiofrequency energy.

This heats the vein until its walls collapse, closing it and sealing it shut. Once the vein has been sealed shut, your blood will naturally be redirected to one of your healthy veins.

Radiofrequency ablation may be carried out under local anaesthetic (you are awake) or general anaesthetic where you're asleep.

The procedure may cause some short-term side effects, such as pins and needles (paraesthesia).

You may need to wear compression stockings for up to a week after having radiofrequency ablation.

Endovenous laser treatment

As with radiofrequency ablation, endovenous laser treatment involves having a catheter inserted into your vein and using an ultrasound scan to guide it into the correct position.

A tiny laser is passed through the catheter and positioned at the top of your varicose vein.

The laser delivers short bursts of energy that heat up the vein and seal it closed. The laser is slowly pulled along the vein using the ultrasound scan to guide it, allowing the entire length of the vein to be closed.

Endovenous laser treatment is carried out under either local or general anaesthetic.

After the procedure you may feel some tightness in your legs, and the affected areas may be bruised and painful. Nerve injury is also possible, but it's usually only temporary.

Ultrasound-guided foam sclerotherapy

If endothermal ablation treatment is unsuitable for you, you'll usually be offered a treatment called sclerotherapy instead.

This treatment involves injecting special foam into your veins. The foam scars the veins, which seals them closed.

This type of treatment may not be suitable if you've previously had deep vein thrombosis.

The injection is guided to the vein using an ultrasound scan. It's possible to treat more than one vein in the same session. 

Foam sclerotherapy is usually carried out under local anaesthetic, where a painkilling medication will be used to numb the area being treated.

After sclerotherapy, your varicose veins should begin to fade after a few weeks as stronger veins take over the role of the damaged vein, which is no longer filled with blood.

You may require treatment more than once before the vein fades, and there's a chance the vein may reappear.

Although sclerotherapy has proven to be effective, it's not yet known how effective foam sclerotherapy is in the long term. NICE found, on average, the treatment was effective in 84 out of 100 cases.

But in one study, the varicose veins returned in more than half of those treated.

Sclerotherapy can also cause side effects, including:

• blood clots in other leg veins
• headaches
• lower back pain
• changes to skin colour – for example, brown patches over the treated areas
• fainting
• temporary vision problems

You should be able to walk and return to work immediately after having sclerotherapy. You'll need to wear compression stockings or bandages for up to a week.

In rare cases, sclerotherapy has been known to have serious potential complications, such as strokes or transient ischaemic attacks.

Surgery

If endothermal ablation treatments and sclerotherapy are unsuitable for you, you'll usually be offered a surgical procedure called ligation and stripping to remove the affected veins.

Varicose vein surgery is usually carried out under general anaesthetic, which means you will be unconscious during the procedure.

You can usually go home the same day, but an overnight stay in hospital is sometimes necessary, particularly if you're having surgery on both legs.

If you're referred for surgery, you may want to ask your surgeon some questions, such as:

• who will do my operation?
• how long will I have to wait for treatment?
• will I have to stay in hospital overnight?
• how many treatment sessions will I need?

Read more about questions to ask your doctor.

Ligation and stripping

Most surgeons use a technique called ligation and stripping, which involves tying off the vein in the affected leg and then removing it.

Two small incisions are made. The first is made near your groin at the top of the varicose vein and is approximately 5cm (2in) in diameter.

The second, smaller cut is made further down your leg, usually around your knee. The top of the vein (near your groin) is tied up and sealed.

A thin, flexible wire is passed through the bottom of the vein and then carefully pulled out and removed through the lower cut in your leg.

The blood flow in your legs won't be affected by the surgery. This is because the veins situated deep within your legs will take over the role of the damaged veins.

Ligation and stripping can cause pain, bruising and bleeding. More serious complications are rare, but could include nerve damage or deep vein thrombosis, where a blood clot forms in one of the deep veins of the body.

After the procedure, you may need up to 3 weeks to recover before returning to work, although this depends on your general health and the type of work you do.

You may need to wear compression stockings for up to a week after surgery.

Transilluminated powered phlebectomy

Transilluminated powered phlebectomy is a relatively new treatment, and there's some uncertainty about its effectiveness and safety.

NICE doesn't recommend it as part of the normal treatment plan for varicose veins. But they say the treatment may be offered if your doctor thinks it'll help and the benefits and risks are explained.

During transilluminated powered phlebectomy, 1 or 2 small incisions are made in your leg.

Your surgeon will place a special light called an endoscopic transilluminator underneath your skin so they're able to see which veins need to be removed. The affected veins are cut before being removed through the incisions using a suction device.

Transilluminated powered phlebectomy can either be carried out under general anaesthetic or local anaesthetic. You may experience some bruising or bleeding afterwards.

Varicose veins can cause complications because they stop your blood flowing properly.

Most people who have varicose veins won't develop complications. If they do, it's usually several years after varicose veins first appear.

Some possible complications of varicose veins are explained below.

Bleeding

Varicose veins near the surface of your skin can sometimes bleed if you cut or bump your leg. The bleeding may be difficult to stop.

You should lie down, raise your leg and apply direct pressure to the wound. Seek immediate medical advice if this doesn't stop the bleeding.

Blood clots

If blood clots form in veins located just under the surface of your skin (superficial veins), it could lead to conditions such as: 

• thrombophlebitis – swelling (inflammation) of the veins in your leg
• deep vein thrombosis – which can cause pain and swelling in the leg, and may lead to serious complications like pulmonary embolism

Chronic venous insufficiency

If the blood in your veins doesn't flow properly, it can interfere with the way your skin exchanges oxygen, nutrients and waste products with your blood.

If the exchange is disrupted over a long period of time, it's known as chronic venous insufficiency.

Chronic venous insufficiency can sometimes cause other conditions to develop, including:

• varicose eczema – a condition that causes your skin to become red, scaly and flaky
• lipodermatosclerosis – which causes your skin, usually around the calf area, to become hardened and tight, and you may find it turns a red or brown colour
• venous leg ulcers – this develops when there's increased pressure in the veins of your lower leg, which may eventually cause an ulcer