What Causes Varicose Veins

If you’ve ever looked down at your legs and noticed bulging, twisted veins near the surface of the skin, you’ve probably wondered, what causes varicose veins? Varicose veins develop when the valves inside your veins weaken or become damaged, causing blood to flow backward and pool in the legs. This pooling increases pressure inside the veins, stretching them and making them bulge near the surface of the skin.

At CACVI, we’ve been diagnosing and helping patients treat varicose veins for over 30 years, and we understand that every case is different. Our experienced vascular specialists use advanced tools like duplex ultrasound during a thorough physical exam to evaluate blood flow and identify the root cause of your condition. If you’re concerned about symptoms or want expert guidance, you should schedule a consultation with us today!

In this post, we’ll break down the most common causes of varicose veins and explain the key risk factors for them. We’ll also explore how these veins look, what symptoms may include, and when the condition becomes more serious.

What Are Varicose Veins?

Varicose veins are enlarged, twisted and typically visible beneath the skin, most commonly appearing in the legs. They develop when weakened or damaged vein valves allow blood to flow backward and pool instead of moving efficiently toward the heart. Over time, this increased pressure causes the vein to stretch, bulge, and become visible at the surface of the skin. Chronic venous insufficiency (CVI), a condition that impairs blood flow in the veins over time, often coexists with varicose veins. In our experience at CACVI, many people initially think varicose veins are only a cosmetic concern. However, they are actually a common medical condition that can progress if left untreated. According to the Society for Vascular Surgery, approximately 40 million people in the United States have varicose veins, and nearly 1 in 4 adults will develop them at some point. Studies also show that chronic venous insufficiency affects up to 40% of the U.S. population to varying degrees. As Dr. Vasim Lala explains, “Varicose veins are not simply a cosmetic issue. They are often a sign of underlying venous reflux, which happens when blood is not flowing properly back to the heart. Early evaluation helps us prevent more serious complications.” We couldn’t agree more. When we perform a physical exam and confirm findings with duplex ultrasound, we’re not just looking at what you see on the surface; we’re evaluating how your blood is actually flowing. For example, one of our patients, a 46-year-old teacher, came to us thinking she just had “ugly veins” after years of standing in the classroom. In some cases, like hers, people delay care because the symptoms seem minor. However, her ultrasound revealed underlying venous reflux consistent with early chronic venous insufficiency. With timely, minimally invasive treatment and simple lifestyle changes, we were able to improve her symptoms and help prevent further complications. Had she waited longer, she may have developed skin discoloration or more serious health problems. Varicose veins most often affect the legs because standing or sitting for long periods increases pressure in the lower body. The veins in your legs have to work harder to push blood upward against gravity. If the valves weaken, blood begins to pool, causing the veins to enlarge. Over time, symptoms may include pain, swelling, itching, skin discoloration, or even ulcers in more advanced cases.

How Do Varicose Veins Develop?

Varicose veins develop because of a blood flow problem inside the veins. Typically, veins carry blood back to the heart, working against gravity, especially in the legs. To make this possible, your veins contain tiny one-way valves that open to let blood move upward and close to prevent it from flowing backward. When those valves weaken or become damaged, blood begins to leak backward and collect inside the vein. This backward flow is known as venous reflux. Instead of efficiently returning to the heart, blood pools in the veins, increasing pressure inside the blood vessels. Over time, that pressure causes the vein to stretch, enlarge, and bulge near the surface of the skin. This is when you begin to see varicose veins. In our experience, this process doesn’t happen overnight. It usually develops gradually. For instance, if you spend long periods standing or sitting, the pressure in your lower legs increases. If you also have a family history of vein problems or other risk factors, the valves may weaken faster. One small valve failure can lead to increased pressure in connected veins, creating a chain reaction. We often explain it to patients this way: imagine a series of doors meant to swing in one direction. If one door doesn’t close properly, everything behind it backs up. That’s essentially what happens with venous reflux. Over time, the continuous pooling causes the vein walls to expand and become twisted veins. Dr. Vasim Lala frequently emphasizes, “Venous reflux is the underlying cause of most symptomatic varicose veins. If we don’t address the reflux, we’re not addressing the root of the problem.” That’s why a proper physical exam and duplex ultrasound are so important. They allow us to see exactly where reflux is occurring and how severe it is. It’s also important to note that contrary to popular opinion, varicose veins aren’t limited to women. In fact, many men are surprised to learn they can develop the condition as well. Yes, varicose veins can affect any gender.

10 Common Causes and Risk Factors for Varicose Veins

In our experience, varicose veins usually develop for multiple reasons. Multiple risk factors can increase pressure in the leg veins, weaken vein valves, and disrupt healthy blood flow. Below are the most common causes of varicose veins and key risk factors for them that we see every day in clinical practice:

1. Genetics

Genetics and varicose veins are strongly connected. If one or both of your parents had varicose veins, your risk significantly increases. Research suggests that if both parents are affected, your risk may be as high as 80–90%. We often tell patients that if visible veins run in your family history, don’t ignore early symptoms.

2. Age

As we age, the vein walls and valves naturally weaken. Veins are often less elastic over time, which makes it harder for them to push blood back toward the heart. According to vascular health data, varicose veins affect up to 40% of women and 20% of men over age 50. Aging doesn’t guarantee you’ll develop them, but it does increase risk.

3. Pregnancy

Pregnancy increases blood volume and places extra pressure on the veins in the legs. Hormonal changes also relax vein walls. In many cases, varicose veins that appear during pregnancy improve afterward, but sometimes the valve damage remains. If you’re pregnant and noticing swelling or visible veins, we recommend monitoring symptoms closely.

4. Prolonged Standing or Sitting

Standing or sitting for long periods is one of the most common risk factors we see. Nurses, teachers, retail workers, factory workers, and office employees are especially vulnerable. When you stay in one position for long periods, blood can pool in the lower legs. One way to help prevent this problem is by moving every 30–60 minutes to help blood circulate.

5. Obesity or Excess Weight

Obesity and varicose veins are closely linked. Extra weight increases pressure in the lower extremity veins, making it harder for blood to return to the heart. Maintaining a healthy weight can significantly reduce strain on your blood vessels and help prevent progression.

6. Hormonal Changes

Hormones affect vein strength. Birth control pills, menopause, and hormone replacement therapy can relax vein walls and contribute to valve weakness. However, it depends on the individual, as not everyone on hormone therapy will develop varicose veins. But it is a known risk factor.

7. Previous Blood Clots (DVT)

A prior deep vein thrombosis (DVT) can damage vein valves permanently. Once the valves are impaired, blood flow may become abnormal, leading to chronic swelling and visible veins. According to the CDC, up to 30–50% of patients with DVT may develop post-thrombotic syndrome, a form of chronic venous insufficiency.

8. Sedentary Lifestyle

A sedentary lifestyle and varicose veins often go hand in hand. When your calf muscles aren’t actively contracting, they can’t help push blood upward. As Dr. Vasim Lala explains, “Movement is essential for healthy circulation. The calf muscle acts like a pump and when we don’t use it, blood flow slows and pressure increases in the veins.” Even simple daily walking can help improve circulation.

9. Injury to the Legs

Trauma to the legs can damage veins directly. In some cases, an old sports injury or accident can disrupt normal blood flow. If you’ve had leg trauma and notice new symptoms like swelling or pain, we recommend a vascular evaluation.

10. Chronic Venous Insufficiency (CVI)

Chronic venous insufficiency is a progressive vein disease in which blood consistently pools due to valve failure. According to the Society for Vascular Surgery, CVI affects up to 40% of adults to varying degrees. When left untreated, it can worsen over time and lead to skin changes, ulcers, or other serious health problems. Varicose veins are often an early sign of this condition.

Why Varicose Veins Develop Most Often in the Legs

In our experience, one of the most common questions we hear is, “Why do varicose veins usually appear in the legs and not elsewhere in the body?” The answer largely comes down to gravity and pressure.  Your leg veins work the hardest in your entire body because they must push blood upward against gravity to return it to the heart. According to vascular research published by the Society for Vascular Surgery, venous pressure in the legs while standing can increase to 80–100 mmHg, compared to much lower pressures when lying down. That constant upward battle is what makes the lower extremities especially vulnerable. When you’re standing, blood naturally pulls downward due to gravity. This creates what’s known as hydrostatic pressure, pressure created by fluid weight. The longer you remain standing, the more that pressure accumulates in the veins of your legs. Over time, this increased venous pressure can stretch the vein walls and strain the valves that regulate blood flow. In healthy veins, one-way valves and the calf muscles work together to push blood upward. We often describe the calf muscles as a “second heart.” Every time you walk, your muscles contract and help blood move upward. But if you’re standing or sitting for long periods, that muscle pump isn’t working efficiently. Blood begins to pool, pressure increases, and the risk of varicose veins rises. According to clinical data, occupations that require prolonged standing are associated with a significantly higher prevalence of varicose veins. Some studies estimate that individuals who stand most of the workday may have up to twice the risk compared to those who move regularly. It depends on other risk factors too, such as family history, obesity, or age, but gravity consistently plays a major role. For instance, we’ve seen patients who feel fine in the morning but notice swelling and heaviness by late afternoon. That’s not a coincidence. The longer you’re upright, the more pressure builds in the leg veins. Over months or years, this repeated stress can weaken valves and cause the vein to bulge near the surface of the skin. The good news? You can help reduce this pressure. We recommend taking short walking breaks every 30–60 minutes, elevating your legs when possible, maintaining a healthy weight, and wearing compression stockings if advised by your doctor. Small, consistent habits can help blood flow more efficiently and reduce strain on your veins over time.

Early Warning Signs of Developing Varicose Veins

Many people ignore the early symptoms of varicose veins because they seem minor at first. You may not see large, twisted veins yet, but your body often gives subtle warning signs that blood flow isn’t working as it should. Recognizing these early symptoms can help prevent more serious health problems and complications of varicose veins down the road. If you catch these signs early, treatment is often simpler and more effective. Here are the most common early warning signs to watch for:

1. Leg heaviness
2. Swelling in the ankles
3. Aching or throbbing pain
4. Night cramps
5. Itchy or discolored skin
6. Spider veins appearing first

When Varicose Veins Become a Medical Concern

In our experience, many people assume varicose veins are simply cosmetic. However, untreated vein disease can worsen over time, especially when underlying venous reflux continues to increase pressure in the legs. It depends on the severity of valve damage and individual risk factors, but ignoring symptoms can lead to progressive complications. We’ve seen firsthand how early intervention can prevent serious health problems and how delaying care can allow a manageable condition to become much more complex. Below is a clear breakdown of when varicose veins move from a cosmetic issue to a medical concern.

Condition	What It Means	Why It’s a Concern
Skin Changes (Stasis Dermatitis)	The skin around the ankles may become red, itchy, dry, or darkened due to chronic inflammation and poor blood flow.	Persistent pressure in the veins causes fluid leakage into surrounding tissue, damaging the skin over time. Without treatment, this can progress.
Leg Ulcers	Open sores, usually near the ankles, that heal slowly.	Venous ulcers are a sign of advanced chronic venous insufficiency. They can become infected and significantly impact quality of life.
Recurrent Swelling	Ongoing swelling in the lower legs that worsens throughout the day.	Chronic swelling indicates sustained venous pressure and impaired circulation, which may continue to worsen without treatment.
Blood Clots	Painful, hardened areas along a vein or sudden swelling.	Varicose veins can increase the risk of superficial thrombophlebitis or, in rare cases, deeper vein clots. A blood clot requires immediate medical evaluation.
Chronic Venous Insufficiency (CVI)	A progressive condition where veins can no longer efficiently return blood to the heart.	According to vascular health data, CVI affects up to 40% of adults to varying degrees and can worsen over time if left untreated.

For example, one of our patients, initially came in because of mild swelling and visible veins. He assumed it was “just part of getting older” and waited nearly two years before seeking care. By the time we evaluated him, he had developed skin discoloration consistent with early stasis dermatitis. Fortunately, after a thorough physical exam and duplex ultrasound, we were able to treat the underlying venous reflux with a minimally invasive procedure and prevent progression to ulcers. If he he waited longer, his risk of more serious complications would have increased significantly.

In some cases, varicose veins remain stable for years. In other cases, especially when multiple risk factors are involved, the condition progresses more quickly. That’s why we always recommend early evaluation rather than a “wait and see” approach. A simple vascular assessment can determine whether your veins are stable or showing signs of chronic disease.

What Are the Treatment Options for Varicose Veins?

One of the biggest misconceptions about varicose veins is that surgery is the only solution. The truth is, treatment depends on the severity of the condition, your symptoms, and whether underlying venous reflux is present.  Some people can manage symptoms with conservative care, while others benefit from minimally invasive medical procedures. It really depends on your specific risk factors, overall health, and how advanced the vein disease has become. Before recommending treatment, we typically perform a physical exam and duplex ultrasound to evaluate blood flow. That step is important because treating the surface veins without addressing the root cause can lead to recurrence.

Non-Surgical Treatments

For patients with mild symptoms, non-surgical options can be effective at managing discomfort and slowing progression. Compression stockings are often the first recommendation. These specialized garments apply graduated pressure to the legs, helping veins push blood back toward the heart and reducing swelling. Many people notice improvements in leg heaviness and aching when they wear compression consistently. However, it’s important to understand that compression stockings do not repair weakened vein valves. They help manage symptoms, but they do not eliminate varicose veins. Lifestyle changes are another important part of conservative treatment. In many cases, improving daily movement can significantly improve circulation. We recommend walking regularly to activate the calf muscle pump, elevating your legs when resting, maintaining a healthy weight to reduce pressure on the lower extremities, and avoiding long periods of standing or sitting whenever possible. For instance, we’ve seen office employees reduce swelling simply by setting a timer to stand and move every 45 minutes. While these changes can help prevent worsening, they may not reverse established varicose veins.

Surgical and Medical Procedures

When symptoms persist or worsen, or when chronic venous insufficiency is diagnosed, medical procedures may provide more definitive relief. Today, many treatments are minimally invasive and performed in an outpatient setting with little downtime. Sclerotherapy is commonly used for smaller varicose veins and spider veins. During this procedure, a medical solution is injected into the affected vein, causing it to collapse and gradually fade from view. Most patients resume normal activities quickly, though mild bruising or temporary swelling can occur. Endovenous laser treatment, sometimes referred to as laser surgery, targets the underlying venous reflux. A thin laser fiber is inserted into the vein, and controlled heat is used to close it. Once the malfunctioning vein is sealed, blood is naturally redirected to healthier veins. In our experience, this procedure is highly effective, with success rates for vein closure often exceeding 90 percent when properly indicated. Recovery is typically fast, and many patients return to normal routines within a day. Vein stripping is a more traditional surgical approach in which the damaged vein is physically removed. While it is less commonly performed today due to advances in minimally invasive techniques, it may still be recommended in certain severe cases. Recovery time is generally longer, and there may be more post-procedure discomfort compared to modern alternatives. The best treatment approach depends on your individual condition. In some cases, conservative measures are sufficient. In others, addressing the underlying venous reflux with a minimally invasive procedure can significantly improve symptoms and reduce the risk of long-term complications. Early evaluation gives you more options and better outcomes.

How Can Varicose Veins Be Prevented?

In our experience, not all varicose veins can be completely prevented, especially when strong genetics and varicose veins run in your family history. But there are meaningful steps you can take to reduce your risk. Prevention focuses on improving blood flow, lowering pressure in the leg veins, and protecting the valves that help blood return to the heart. It depends on your individual risk factors, but small, consistent lifestyle habits can make a significant difference over time.

Lifestyle Modifications

Regular exercise is one of the most effective ways to help prevent varicose veins. Walking, cycling, and swimming activate the calf muscles, which act as a natural pump to help blood move upward against gravity. When the calf muscles contract, they help push blood through the veins and reduce pooling. We often recommend at least 30 minutes of moderate activity most days of the week to support healthy circulation. Maintaining a healthy weight is equally important. Excess weight increases pressure in the lower extremities, placing added strain on vein walls and valves. Obesity and varicose veins are closely connected because higher body weight means more pressure inside the veins. Even modest weight reduction can improve symptoms and lower long-term risk. Avoiding prolonged standing or sitting is another key preventive step. When you remain in one position for long periods, blood can pool in the legs, increasing hydrostatic pressure. If your job requires standing or sitting, we recommend moving every 30 to 60 minutes, flexing your ankles, or taking short walking breaks to help blood circulate. For example, one of our patients, Angela, worked in retail and stood for nearly eight hours a day. She began noticing leg heaviness and early visible veins. After we evaluated her, we recommended compression stockings, scheduled walking breaks, and simple calf exercises during her shifts. Within a few months, her swelling improved and her symptoms stabilized. While lifestyle changes don’t reverse damaged valves, they can significantly slow progression and reduce discomfort.

Early Detection and Management

Prevention also means recognizing early symptoms and acting quickly. As Dr. Vasim Lala often explains, “The earlier we identify venous reflux, the easier it is to manage and prevent progression. Waiting allows pressure to build and damage to continue.” That’s why we emphasize proactive monitoring. If you notice leg heaviness, swelling, spider veins, or skin changes, don’t ignore them. Regular monitoring of symptoms and early evaluation through a physical exam and duplex ultrasound can help determine whether underlying chronic venous insufficiency is developing. In some cases, early intervention with minimally invasive treatment can prevent more serious health problems later. We also advise patients to avoid self-treatment methods that could worsen the condition. For instance, massaging prominent varicose veins may not be safe in certain situations, especially if a blood clot is present.

Don’t Ignore the Signs of Vein Disease

Understanding what causes varicose veins is only the first step. Acting on that knowledge is what truly protects your long-term vein health. In our experience, the difference between a simple, minimally invasive treatment and a more complicated vascular condition often comes down to timing.  Vein disease is progressive, which means it usually does not resolve on its own. The earlier we evaluate the underlying blood flow issue, the more options you have to treat varicose veins effectively and prevent serious health complications. If you’re noticing leg heaviness, swelling, visible veins, or skin changes, don’t wait for symptoms to worsen. When you’re ready, schedule a consultation through our contact page so we can perform a thorough evaluation and determine the right treatment plan for you. You can also view our location and patient reviews on Google to see why so many patients trust CACVI with their vascular health.

Frequently Asked Questions

Below are answers to some of the most common concerns we hear in our clinic.

What Are The Risk Factors For Developing Varicose Veins?

Risk factors for varicose veins include genetics and varicose veins running in your family history, aging, pregnancy, obesity, prolonged standing or sitting, and a sedentary lifestyle. These factors increase pressure in the leg veins and can weaken the valves that help blood flow back to the heart.

Can Exercise Help Prevent Varicose Veins?

Yes, regular exercise helps improve circulation and supports healthy blood flow by activating the calf muscles, which act as a pump for the veins. While exercise may not completely prevent varicose veins, it can significantly reduce progression and symptoms.

Are There Natural Remedies To Alleviate Varicose Vein Symptoms?

Lifestyle changes such as elevating your legs, maintaining a healthy weight, wearing compression stockings, and staying active can help relieve swelling and discomfort. However, natural approaches manage symptoms rather than correcting damaged vein valves.

Do Varicose Veins Always Require Medical Treatment?

Not always, as mild cases may be managed with conservative care and monitoring. However, if symptoms worsen, skin changes develop, or chronic venous insufficiency is present, medical evaluation is strongly recommended.

How Do Varicose Veins Differ From Spider Veins?

Varicose veins are larger, twisted veins that bulge beneath the surface of the skin and may cause pain or swelling. Spider veins are smaller, thinner visible veins that appear closer to the surface and are often more cosmetic, though they can still signal underlying vein issues.

✓ Medically reviewed by

Dr. Mehran J. Khorsandi

M.D., CCDS, FACP, FACC, FSCAI · Interventional and endovascular cardiology

Five board certifications and more than thirty years performing complex cardiovascular and vascular interventions. On the attending staff at Cedars-Sinai since 1993, where he has performed over ten thousand cardiac procedures.

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Board certification verifiable through the American Board of Internal MedicineLast reviewed September 2026