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Venous Disorders: What Are They, and How Do They Work?

Chronic venous disorders describe a number of different vascular problems that affect the lower legs. The health issues associated with venous disorders compound one another and cause worsening conditions that become chronic. According to the Centers for Disease Control and Prevention, "Chronic diseases are defined broadly as conditions that last 1 year or more and require ongoing medical attention or limit activities of daily living or both." While many chronic venous disorders cannot be cured, preventative treatments give you tools to keep them from worsening. As an example, compression socks and stockings support healthy vascular function, and that’s why doctors recommend them to help prevent mild venous disorders from becoming severe. Additional treatments for venous conditions include medications, vascular surgeries, laser treatments, and sclerotherapy.

Venous disorders often introduce deteriorating conditions inside the veins, which may develop into varicose veins, edema, and venous ulcers. Although many people use the term "venous disorder" interchangeably with Chronic Venous Insufficiency (CVI), venous disorders include even the earliest presentation of vein problems, which usually begin with increased venous pressure in the lower legs. Researchers and doctors typically use the Clinical-Etiology-Anatomy-Pathophysiology (CEAP) scale to classify and evaluate venous disorders. Within this classification framework, the following clinical categories are used:

C0 | No signs of venous disease

C1 | Spider veins

C2 | Varicose veins

C3 | Edema

C4a | Pigmentation or eczema 

C4b | Lipodermatosclerosis or atrophie blanche

C5 | Healed ulcer

C6 | Active ulcer


According to a 2018 article in the International Journal of Molecular Sciences, chronic venous disorders have a major impact across the healthcare industry. They account for as much as 2.5% of total health care budgets in developed countries, and these disorders affect 73% of women and 56% of men. Venous disorders often begin with the feeling of heaviness in the legs and without visible symptoms. 

Types of Venous Disorders

Venous disorders range from mild to severe. In some cases, venous disorders even lead to fatal embolisms. Below, we’ve provided some information about different venous disorders and their symptoms.

Superficial Thrombophlebitis

Phlebitis, or swelling of the vein, can occur within a deep vein or within a superficial vein closer to the skin. Superficial thrombophlebitis describes swelling caused by a blood clot in a vein that lies close to the skin's surface. The following symptoms can affect a leg with superficial thrombophlebitis:

  • Warmth or pain near the vein
  • Redness
  • Swelling

Deep Vein Thrombosis 

Deep vein thrombosis (DVT) describes a blood clot that forms in a deep vein, rather than a superficial vein. This type of blood clot can be particularly dangerous, since it can lead to a fatal pulmonary embolism. DVT can cause symptoms such as:

  • Swelling (often in only one leg)
  • A cramping pain in the calf
  • Warm skin
  • Discolored skin
  • Severe pain in the foot or ankle

Spider Veins

Spider veins, also called telangiectasia, form when a vessel close the surface of the skin bursts. The only symptom is typically blue (or red) threadlike lines that appear on the skin's surface.

Varicose Veins 

Varicose veins form when the one-way valves inside the vein cease to function properly, allowing blood to pool in the legs and press against the wall of the vein. When this happens, bulbous blue veins begin to protrude from the skin. Symptoms may include:

  • Heavy, aching legs
  • Burning, throbbing, or cramping in the lower legs
  • Swelling
  • Discomfort when sitting or standing
  • Itching near the vein
  • Skin discoloration 
  • Protruding, bulbous leg veins

Chronic Venous Insufficiency (CVI) 

Venous insufficiency describes chronic venous disorder that has progressed to a stage where the valves and venous walls have failed, causing blood to pool in the legs. Symptoms of chronic venous insufficiency include:

  • Swelling 
  • Tight, itchy skin
  • Pain when walking
  • Skin discoloration, especially brown skin near the ankles
  • Varicose veins
  • Leg ulcers
  • Restless legs
  • Cramps or spasms

Venous Edema 

Sometimes, CVI causes chronic leakage of venous fluid into the tissues of the legs. Venous edema compromises lymphatic function and shares many of the characteristics of lymphedema. ("Lymphadema") Symptoms may include:

  • Pain or itching
  • Restless legs
  • Swelling
  • Cramps or spasms
  • Skin changes
  • Varicose veins
  • Leg ulcers

Post-Thrombotic Syndrome

After experiencing a deep vein blood clot, some patients have damage to the vein. This can cause chronic pain in the weeks and months following the DVT. For a person with  post-thrombotic syndrome, the leg affected by DVT may display the following symptoms:

  • Heaviness or aching
  • Itching, tingling, or cramping 
  • Pain that’s worse with standing
  • Widening of leg veins
  • Swelling
  • Skin changes
  • Ulcers

Venous Ulcers

Varicose veins, post-thrombotic syndrome, and venous insufficiency can all cause open sores, also called venous ulcers. Typically these ulcers form near the ankle as a result of blood pooling in the lower legs, and they can recur multiple times over the course of months or even years. 

What Causes Venous Disorders? 

Chronic venous disorders result from valve dysfunction and venous reflux, but what causes the vein to misbehave in the first place? 

Early Stage

Some of the risk factors for early-stage chronic venous disorders include standing or sitting for long periods of time, which can put additional stress on the circulatory system. Whenever the lower leg maintains an upright position, the blood must flow against the force of gravity to get to the heart. By staying in an upright position for many hours at a time, the veins in your leg face more pressure and strain than they would under different circumstances. 

A family history of venous disorder can also make someone more likely to develop venous reflux. In fact, a 2018 study published in Circulation identified 30 genetic loci associated with varicose veins. (Fukaya) Blood clots and hormonal changes have also been linked to the onset of venous disorders. 

Moderate Venous Disease 

When it comes to middle-stage chronic venous disorders, such as spider veins and mild varicose veins, researchers explain, "Venous hypertension can lead to venous dilatation, worsening valve insufficiency, and generation of a perpetuating cycle of increasing pressure and further dilation." (Ligi 1) In layman's terms, what began as mild pressure and stress within the leg veins can develop into the failure of crucial vein valves and vein walls. When these structures fail, the blood flows backwards, causing additional pressure and stress. The circumference of the vein begins to expand, and the cells that line the interior surface of lymphatic and blood vessels cease to function normally. 

Once someone develops varicose veins, they become more prone to stagnant blood and experience a higher risk of clotting. Again, genetic factors make some people especially susceptible to compounding vascular problems. According to the researchers who studied the genetic markers for varicose veins, "These [genetic] loci appear particularly interesting given the strong genetic overlap that we discovered between varicose veins and DVT [deep vein thrombosis]." (Fukaya) CVI can cause venous stasis, with poor circulation that allows blood clots to form. At the same time, a blood clot can also be the cause of further venous insufficiency, since a clot can cause increased pressure on the vein walls and additional dilation of the affected vein. For this reason, chronic venous disorders are sometimes referred to as "a vicious cycle". (Ligi)

Severe Cases

As chronic venous disorder worsens, chronic venous insufficiency can trigger severe health problems, including severe varicose veins, venous edema, and ulcers. Plus, DVT can cause a fatal pulmonary embolism, along with a condition called post-thrombotic syndrome. The syndrome is associated with long-term vein damage and clotting problems. Researchers explain the cycle of causation, clarifying, "It is noteworthy that the late stages of CVeD [chronic venous disorders], mainly identified as CVI, are frequently caused by a post-thrombotic syndrome." (Ligi 7) So, the venous disorder causes DVT, which causes post-thrombotic syndrome, which causes worsening venous insufficiency. 

To make matters worse, many of the problems associated with chronic venous disorder are likely to recur. For instance, one study estimated the likelihood of recurrence for someone with a medical history of DVT is 40% after 10 years. (Prandoni Abstract) Seasonality may be a contributing factor for recurrent venous ulcers, as well. A 2011 study in the Journal of the European Academy of Dermatology and Venereology showed that venous ulcers are more likely to develop in the fall and winter. (Abstract

Treatment Options 

To begin, it's important to have your symptoms evaluated by a doctor. You may notice that many of the symptoms listed above fit with multiple venous disorders. For instance, leg swelling, a feeling of heaviness, and skin changes might equally describe a number of different vascular problems. To better assess your circulatory health, a doctor may choose to perform a duplex ultrasound on your legs. An ultrasound will allow your doctor to identify any blood clots and damaged veins. Plus, he or she can assess the velocity and direction of blood flow within your veins. 

Compression Garments

If you do have a venous disorder, it's likely that your doctor will recommend compression therapy as an initial treatment. Compression socks and stockings support the veins of the leg by exerting gentle pressure. By reducing the circumference of the vein, a compression garment improves the velocity of blood flow. Faster blood flow enables your veins to carry blood more efficiently. With less stress on the vein valves and vein walls, you can slow the progress of chronic venous disorders.

In addition, graduated compression garments feature more pressure at the ankle and less pressure at the calf. This pressure gradient works to push the fluid away from the ankle, ultimately helping to prevent blood from pooling in the ankles. Graduated pressure supports the work of your veins, as they move the deoxygenated blood and waste fluids up your leg and against the force of gravity. Compression therapy also works to reduce feelings of heaviness and pain caused by venous disorders. 

Even for the most severe venous disorders, compression socks have been proven to be impactful. In a comprehensive review of scientific literature on graduated compression garments, researchers concluded: "Many studies that investigated the effectiveness of graduated compression stockings in patients of all CEAP classes reported improvement in symptoms such as pain and swelling and in activity levels and well-being." (Lim E392) Moreover, they found particularly strong evidence for the use of graduated compression socks for those patients with leg ulcers—active ulcers are ranked C6 on the CEAP Index. They write, "High-quality evidence supports their use by patients with chronic venous insufficiency, especially those with ulcers." (E397)

Radiofrequency or Laser Ablation 

For people with moderate varicose veins, thermal ablation offers a way to close off a dysfunctional vein. The doctor uses heat to damage the vein, causing scar tissue to form and block off the vein from the rest of the circulatory system. 


A common treatment for spider and varicose veins, sclerotherapy involves the application of a chemical solution into the damaged vein. After treatment, the vascular system reroutes blood to other veins.

Vein Stripping and Microphlebectomy

Both of these invasive procedures involve making surgical incisions to physically remove veins. Microphlebectomy refers to the removal of smaller, unnamed veins; whereas, vein stripping, also called ligation, describes the process of surgically removing larger veins. 


Doctors often prescribe anticoagulants for patients with DVT, and these can be used in combination with compression therapy. The goal of blood thinning medication is to prevent blood clots from worsening and to prevent them from breaking off and forming a pulmonary embolism. 

Vena Cava Filters 

In some cases, a doctor will surgically insert a vena cava filter to catch blood clots and prevent them from traveling through the bloodstream to the lung. 

Dealing with a Chronic Condition

If you’re dealing with chronic venous disorder, you probably need support. Learn how compression socks can help you in every stage of your health journey. Whether you’re recovering from vein surgery or hoping to prevent swelling, try using compression socks in combination with other treatments to help stop the “vicious cycle” in its tracks. 



“About Chronic Diseases.” National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, 23 Oct. 2019, www.cdc.gov/chronicdisease/about/index.htm.

Fukaya, Eri et al. "Clinical and Genetic Determinants of Varicose Veins." Circulation, vol. 138, iss. 25, pp. 2869-2880, Dec. 2018, https://www.ahajournals.org/doi/epub/10.1161/CIRCULATIONAHA.118.035584

Klode, J et al. “Relationship between the seasonal onset of chronic venous leg ulcers and climatic factors.” Journal of the European Academy of Dermatology and Venereology, vol. 25, iss. 12, pp. 1415-1419, 2011, https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1468-3083.2011.03988.x.

Ligi, Daniela et al. “Chronic Venous Disorders: The Dangerous, the Good, and the Diverse.” International journal of molecular sciences vol. 19, iss. 9, 2544. 28 Aug. 2018, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6164218/pdf/ijms-19-02544.pdf

Lim, Chung Sim and Alun H. Davies. “Graduated compression stockings.” CMAJ. Vol. 186, Iss. 10 pp. E391-E398. July 08, 2014, https://www.cmaj.ca/content/cmaj/186/10/E391.full.pdf.

“Lymphedema and Venous Edema.” UW Health, University of Wisconsin Hospitals and Clinics Authority, 21 Mar. 2018, www.uwhealth.org/physical-therapy-occupational-therapy-speech-therapy/lymphedema-and-venous-edema/13987.

Prandoni, Paolo et al. “The risk of recurrent venous thromboembolism after discontinuing anticoagulation in patients with acute proximal deep vein thrombosis or pulmonary embolism. A prospective cohort study in 1,626 patients.” Haematologica vol. 92, iss. 2, 2007, pp. 199-205, https://pubmed.ncbi.nlm.nih.gov/17296569/.

Zegarra TI and Tadi P. "CEAP Classification Of Venous Disorders." StatPearls, StatPearls Publishing, 31 May 2020, https://www.ncbi.nlm.nih.gov/books/NBK557410/.

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