Updated:
by
Clare E. Nguyen, MD
Medically reviewed by Clare E. Nguyen, MD
Swollen ankles, aching legs, itchy skin near the ankle, or slow-healing sores can have several causes. If you have diabetes, it is tempting to blame every leg symptom on blood sugar. However, venous insufficiency may also play a role. Venous insufficiency is a condition in which the valves inside your leg veins stop working as they should, allowing blood to flow backward and pool in your lower legs.
Diabetes and venous disease are different conditions and one does not directly cause the other. However, they can occur in the same person and share several risk factors. When both conditions are present, small problems can become bigger ones.
The challenge is determining how much of your leg symptoms are due to veins. It starts with a painless ultrasound.
Veins carry blood from the legs back to the heart. One-way valves help keep blood moving upward. When the valves become damaged or weak, blood can pool in the legs, causing chronic venous insufficiency (CVI). Pooled blood raises pressure inside the vein, pushing fluid into nearby tissue.
Cleveland Clinic reports that CVI affects about 1 in 20 adults. Varicose veins, the ropey bulging veins you can see near the surface, are more common, appearing in about 1 in 3 adults. They can be an early sign of the same valve problem. Each year, roughly 1 in 50 adults with varicose veins go on to develop CVI.
CVI symptoms include:
Diabetes can affect the legs through nerve and artery damage. Years of high blood sugar injure nerves. Mayo Clinic reports that this nerve damage, called diabetic neuropathy, may affect up to half of people with diabetes. In the feet and lower legs, it can cause numbness, decreased sensation of pain or temperature, tingling, burning, and sharp pain.
Diabetes also increases the risk of peripheral artery disease (PAD). The American Heart Association explains that high blood sugar causes inflammation that injure blood vessels and makes plaque buildup more likely. That narrowing is called peripheral artery disease. Symptoms include pain or cramping with walking, cool feet, color changes, numbness, and wounds that heal slowly.
Diabetes tends to affect nerves and arteries. Venous insufficiency affects veins.
If you are not sure whether vein disease is causing your leg pain, our Vein Symptom Quiz takes a few minutes and can help you decide on your next step.
No, diabetes does not cause venous insufficiency. The National Library of Medicine's MedlinePlus list of the main risk factors for chronic venous insufficiency includes a history of deep vein thrombosis (a blood clot in a deep leg vein), a family history of the condition, obesity, pregnancy, prolonged sitting or standing, older age, greater height, and being female. Stanford Medicine lists smoking and insufficient physical activity as well.
Now compare that list to the risk factors for diabetes. UCSF Health reports that type 2 diabetes accounts for 90–95% of diabetes cases and that 80 percent of people with type 2 diabetes are overweight. The disease is usually diagnosed in adults over 40, though it is showing up in younger people more often. Weight and age appear on both lists.
Chronic venous insufficiency and diabetes share overlapping risk factors so often appear in the same person.
Both conditions cause swelling and unusual sensations, so they're easy to confuse. A few patterns help.
Signs that point to vein problems:
Signs that point to diabetes-related nerve or artery damage:
Ulcer location is an important clue. Venous ulcers most often form around the ankles, driven by sustained high pressure inside leg veins. NYU Langone Health describes diabetic foot ulcers as open sores that develop on the foot. They often start with a small injury, such as a scrape or cut.
Having either condition makes the other harder to manage. Harvard Health notes that loss of feeling raises the risk of foot ulcers because a callus can break down into a sore and become infected before you notice it. The Society for Vascular Surgery explains that decreased circulation weakens skin and tissue, so wounds form and heal more slowly. A small wound can become a bigger one if it is not treated.
Add leaking vein valves (vein disease) to that picture, and you have swelling, fragile skin, and high pressure in the tissue around the ankle. Act promptly on injuries and infections, however minor.
The same habits do double duty for both conditions:
Report any new sore or wound that is not healing, or any red, warm, swollen area to a physician right away.
When leg symptoms have more than one possible cause, the first job is diagnosis. The board-certified vein physicians at Center for Vein Restoration use duplex ultrasound to examine your leg veins. This painless test uses sound waves to show how blood moves and whether valves are leaking.
The result of the ultrasound, along with a physical exam and history, can tell us how much of your leg symptoms are vein-related. When vein disease is causing or contributing to your symptoms, our physicians treat it with minimally invasive outpatient procedures. When the cause sits outside the vein and lymphatic system, we say so. We then connect you with the right specialist. That may be your primary care physician, an endocrinologist, a podiatrist, or a vascular surgeon.
Knowing which part of the problem is venous lets the rest of your care team focus on what isn't.
Q: Can diabetes make varicose veins worse?
A: Diabetes does not cause varicose veins, a symptom of chronic venous insufficiency. A person with diabetes can also have venous insufficiency, neuropathy, or peripheral arterial disease, contributing to leg symptoms. If your varicose veins are aching, swelling, or causing skin changes, that is a reason to see a vein specialist.
Q: What is the difference between a diabetic foot ulcer and a venous ulcer?
A: Location is the biggest tell. Venous ulcers most often form around the ankles, while diabetic foot ulcers are sores that develop on the foot, including the sole and the toes. The underlying causes differ too, so the treatment plans differ. Any open sore on the leg or foot should be seen by a physician promptly.
Q: Is it safe to wear compression socks if I have diabetes?
A: Ask your physician before you start. Compression is a standard part of venous care. However, people with diabetes may also have reduced arterial blood flow which may make compression inappropriate. Your physician can check circulation in your legs and recommend a compression level, or advise against it.
Q: Can I have vein treatment if I have diabetes?
A: Many people with diabetes are evaluated and treated for vein disease. The decision depends on your circulation, your skin condition, and your overall health, which is why the visit starts with imaging rather than a procedure. Your CVR physician will explain what treatment can and cannot address in your case.
Q: Why do my legs swell more in the evening?
A: Gravity works against your leg veins all day. If the valves are leaking, blood and fluid collect in the lower leg as the hours pass, which is why swelling is often worst at night and better after sleep. Evening swelling that keeps coming back is a common early sign of venous insufficiency and is worth having checked.
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