If you suffer from venous ulcers in Houston, you are not alone. Venous ulcers are caused by venous insufficiency. It is essential to contact a physician who specializes in venous insufficiency treatment as soon as you notice any darkening or thickening of the skin. A vein treatment center can treat uncomfortable symptoms and may even be able to prevent an ulcer from forming altogether. Keep reading to learn about common causes of venous ulcers, including venous insufficiency, poor habits, and minor injuries.
Quick Answer: Venous ulcers are caused by long-standing high pressure in the leg veins, called venous hypertension. The most common source is faulty valves in the superficial veins (venous insufficiency), but deep vein damage after a blood clot, a narrowed pelvic vein, leaking perforator veins and a weak calf muscle pump can all produce the same pressure. Obesity, smoking, inactivity, long hours of standing, minor injuries and scratching then tip fragile skin into an open wound. Finding the exact cause with a venous duplex ultrasound is what makes lasting healing possible.
Meet your vein specialist
Dr. Syed Raza, MD
Vascular & Interventional Radiology · Founder, Premier Vein & Vascular Center
Fellowship-trained interventional radiologist certified by the American Board of Radiology and the Royal College of Radiologists (UK). Former Chief of Interventional Radiology at UTMB Galveston and Memorial Hermann Memorial City, with 15+ years treating varicose veins, venous reflux and peripheral arterial disease.
Venous Insufficiency
Venous insufficiency is the underlying cause of venous ulcers. This kind of vascular disease is to blame for more than two-thirds of all leg ulcers. Venous insufficiency is a general term for the condition in which the veins cannot adequately circulate blood out of the legs and feet and back to the heart. When the valves responsible for keeping blood flowing to the heart become damaged, blood can back up. As blood pools around the veins, it exerts pressure on the surrounding healthy tissue, which can lead to venous ulcers.
Lifestyle Habits
Venous ulcers can also be caused by poor habits and lifestyle choices. For example, there is a significant correlation between smoking tobacco products and both arterial and venous ulcers. If a patient already suffers from venous insufficiency and continues to smoke, the risk for venous ulcers increases. Individuals who do not get enough exercise are also at higher risk for developing venous ulcers. When people are sedentary, blood can quickly build up and pool in the lower extremities. Occupations that require many hours of standing can also contribute. Obesity can also contribute to the formation of venous ulcers in patients with venous insufficiency. Excess abdominal fat puts pressure on the veins in the abdomen and pelvis which then causes increased pressure in the veins in the legs.
Minor Injuries and Itching
Venous ulcers may also develop after certain minor injuries. Due to venous insufficiency and lack of adequate blood flow, the skin in the lower legs and ankles is more prone to breaking down and not healing quickly even when minor injuries occur. Venous insufficiency often causes the legs to itch, and frequent scratching can also lead to skin breakdown. When a sore develops on the skin, it can become discolored, hardened, and infected. Without proper treatment, these ulcers can take months or years to heal.
The Common Cause Behind Every Venous Ulcer: Venous Hypertension
Every venous ulcer, whatever triggered it, shares one underlying problem: the pressure in the veins at the ankle stays too high for too long. In a healthy leg, that pressure drops sharply each time you walk, because the calf muscle squeezes blood upward and the valves stop it falling back. In a leg with vein disease, the pressure stays high even while walking. Doctors call this ambulatory venous hypertension.
Sustained high pressure damages the smallest blood vessels in the skin. Fluid and proteins leak out, white blood cells become trapped and release inflammatory substances, and iron from red blood cells stains the skin brown. Over time the tissue becomes swollen, scarred and short of oxygen. At that point a scratch, a bump or even dry, cracked skin can open into a wound that does not close.
So the real question in clinic is not only whether a patient has venous insufficiency, but which part of the venous system is causing the pressure. The answer changes the treatment.
Specific Vein Problems That Cause Venous Ulcers
Superficial vein reflux
This is the most common cause we find. The great saphenous vein, running along the inner leg, or the small saphenous vein, behind the calf, has valves that no longer close. Blood falls back down these veins with every step and pools around the ankle. Superficial reflux is usually very treatable with a minimally invasive procedure.
Leaking perforator veins
Perforator veins connect the surface veins to the deep veins. Their valves normally let blood flow inward only. When they fail, the high pressure of the deep system is transmitted outward, often right beneath the skin where the ulcer forms. Incompetent perforators frequently sit directly under or near an ulcer.
Deep vein damage after a clot
A deep vein thrombosis can scar the deep veins and destroy their valves, even after the clot has dissolved. The long-term result, called post-thrombotic syndrome, causes swelling, heaviness, skin changes and ulcers, sometimes years after the original clot. Some patients never knew they had a clot.
Narrowing of a pelvic vein
The main vein draining the leg passes through the pelvis. If it is narrowed, by old clot or by compression from an overlying artery (often called May-Thurner syndrome, typically on the left side), blood cannot leave the leg easily and pressure rises below the blockage. This cause is easy to miss without targeted imaging.
A failing calf muscle pump
Even with reasonable valves, a calf that does not contract well cannot clear blood from the leg. Stiff ankles from arthritis or old injuries, a shuffling walk, prolonged bed rest, stroke or nerve damage all weaken the pump. In older patients this is often a major contributor alongside valve problems.
Causes of Venous Ulcers Compared
The table below summarizes the main causes, how each one raises pressure, and how we usually find and treat it.
| Cause | How it raises pressure | How it is found | Typical approach |
|---|---|---|---|
| Superficial vein reflux | Blood falls back down the saphenous veins | Venous duplex ultrasound | Ablation, foam sclerotherapy, phlebectomy |
| Incompetent perforator veins | Deep pressure is pushed out into the skin | Venous duplex ultrasound | Targeted ablation or sclerotherapy |
| Post-thrombotic deep vein damage | Scarred deep veins with failed valves | Ultrasound, clot history | Compression, treat superficial reflux, further imaging if needed |
| Pelvic (iliac) vein narrowing | Outflow from the leg is blocked | Specialized imaging when suspected | Evaluation for a venous stent in selected patients |
| Calf muscle pump failure | Blood is not cleared from the leg | Examination of ankle movement and gait | Exercise, physical therapy, compression |
Many patients have more than one of these at the same time. A careful ultrasound often shows, for example, superficial reflux on top of old deep vein damage, which is why a single treatment does not always solve the problem.
Other Health Conditions That Contribute
Several conditions do not cause a venous ulcer directly but make one more likely or slower to heal:
- Peripheral arterial disease, which reduces blood flow into the leg and leads to mixed arterial and venous ulcers. It also limits how much compression is safe. Our page on peripheral arterial disease explains the warning signs.
- Diabetes, which slows wound repair and increases infection risk
- Heart failure and kidney disease, which add fluid to the legs and worsen swelling
- Lymphedema, where the lymph drainage system cannot remove fluid efficiently
- Poor nutrition, particularly low protein intake in older adults
- Some medicines that cause ankle swelling, such as certain blood pressure tablets; never stop them without speaking to your doctor
Why the Ulcer Usually Forms at the Inner Ankle
Venous ulcers have a favorite spot: just above the inner ankle bone. Several reasons combine there. The pressure in the veins is highest at the lowest point of the leg. The great saphenous vein and several important perforator veins run through this area. The skin over the inner ankle is thin, with little fat or muscle underneath to cushion it. Ulcers in unusual places, such as the toes, the top of the foot or high on the shin, should raise the question of a different cause, such as arterial disease, and need careful assessment.
Seek urgent medical care if you notice:
- Sudden swelling, pain and warmth in one calf or thigh, which may be a new deep vein thrombosis
- Chest pain, sudden shortness of breath or coughing up blood
- Spreading redness, red streaks, fever or chills around a leg wound
- A foot that becomes cold, pale, blue or numb, or severe pain in the foot at night
- Heavy bleeding from a varicose vein or ulcer that does not stop with firm pressure and leg elevation
Clues From Your History That Point to the Cause
Symptoms alone cannot confirm which veins are at fault, but certain patterns give us strong hints before the scan begins.
- Long-standing bulging varicose veins, often in several family members, usually point to superficial reflux.
- A previous leg clot, a broken leg in a cast, major surgery or a long hospital stay raises suspicion of post-thrombotic deep vein damage.
- Swelling of the whole left leg, especially in a younger woman, or swelling that started after a clot in the thigh, makes us look carefully at the pelvic veins.
- Stiff ankles, a cane or walker, or mostly sitting during the day suggest the calf pump is part of the problem.
- Pain in the foot at night that eases when the leg hangs down points toward arterial disease rather than, or as well as, a venous cause.
Bringing a list of past clots, surgeries, injuries and medicines to your appointment helps us connect these clues with the ultrasound findings quickly.
How We Find the Cause of a Venous Ulcer
At Premier Vein & Vascular Center, identifying the exact cause is the first step toward a wound that heals and stays healed.
- Focused history. We ask how the wound started, how long it has been present, whether you have had clots, leg injuries or surgery, and about diabetes, heart problems, smoking, mobility and medicines.
- Examination. We look at the ulcer and the skin around it, assess swelling, check ankle movement and gait, and feel the foot pulses.
- Ankle-brachial index. This quick test checks arterial blood flow, which tells us whether compression is safe and whether arterial disease is part of the problem.
- Venous duplex ultrasound. Performed in our IAC-accredited vascular lab, the scan maps reflux in the superficial, perforator and deep veins and looks for old clot. When the pattern suggests a pelvic vein problem, further imaging such as MRI or CT venography may be recommended.
- A clear plan. We explain which veins are responsible and set out a plan that combines wound care, compression and treatment of the cause.
Treating the Cause, Not Just the Wound
Dressings and compression are essential, but they do not remove the source of the pressure. Once the cause is clear, treatment can be targeted:
- Superficial reflux is closed with endovenous thermal ablation or non-thermal vein ablation, office procedures done under local anesthesia that take about an hour.
- Leaking perforators and small veins under the ulcer can be closed with ultrasound-guided foam sclerotherapy.
- Deep vein damage is managed with long-term compression, and treating any coexisting superficial reflux still helps.
- Calf pump weakness improves with walking programs, ankle exercises and, when needed, physical therapy.
- Contributing conditions such as diabetes, heart failure and arterial disease are managed alongside your other doctors.
Most patients walk out after a vein procedure and return to light activity the same day, which matters because walking itself helps the ulcer heal.
Getting the Cause Diagnosed in Houston
If you live in Houston, Katy or the surrounding area and have a leg wound that has lasted more than a few weeks, or skin changes around the ankle that are getting worse, the most useful next step is a full venous and arterial assessment. Dr. Syed Raza, a fellowship-trained interventional radiologist with more than 15 years of experience treating venous reflux, leads our team at a vein clinic in Houston where testing and minimally invasive treatment are done in one place. Same-week appointments are usually available, and most insurance plans, including Medicare, are accepted. Learn more about our approach on the venous ulcer treatment page.
Talk With a Specialist at Premier Vein
Have questions about your symptoms or treatment options? Dr. Syed Raza and the team at Premier Vein & Vascular Center can evaluate your concerns and explain your options clearly. Same-week appointments are usually available, and most insurance plans are accepted.
Frequently Asked Questions
What is the main cause of venous ulcers?
The main cause is sustained high pressure in the leg veins, usually from faulty valves in the superficial veins. Deep vein damage after a blood clot, leaking perforator veins, a narrowed pelvic vein and a weak calf muscle pump can produce the same pressure.
Can a blood clot cause a leg ulcer years later?
Yes. A deep vein thrombosis can permanently damage the deep veins and their valves, leading to post-thrombotic syndrome. Swelling, skin changes and ulcers can appear months or years after the original clot.
Why do venous ulcers keep coming back?
Ulcers recur when the vein pressure that caused them is still present. If the refluxing veins are not treated and compression is stopped, the fragile healed skin often breaks down again.
Can you get a venous ulcer without visible varicose veins?
Yes. Reflux can occur in veins that are not visible from the surface, and deep vein damage or a narrowed pelvic vein may cause ulcers without obvious varicose veins. An ultrasound is needed to find the cause.
Is a leg ulcer always caused by veins?
No. Venous ulcers are the most common type, but arterial disease, diabetes, pressure and other conditions can also cause leg wounds. Checking both the veins and the arteries is important before starting treatment.
Does standing all day cause venous ulcers?
Standing for long hours does not cause ulcers on its own, but it raises pressure in veins that already have weak valves and can speed up skin damage. Movement breaks, calf exercises and compression help offset the effect.
Trusted Health Resources
- Chronic Venous Insufficiency, Society for Vascular Surgery
- Venous Insufficiency, MedlinePlus Medical Encyclopedia (NIH)
- Varicose Veins and Spider Veins, MedlinePlus (NIH)