December 12, 2022

13 Underlying Causes Of Leg Swelling From The Knee Down

Swelling in legs from the knees down can be caused by a variety of things. Find out what might be causing your swollen legs here!

There are many reasons your legs may swell from the knee down. Reasons range from diet, medications, and lifestyle to more serious conditions like vein disorders and circulation problems. This article will explore 13 of the most common causes of leg swelling. By understanding the underlying cause of your swelling, you can take steps to address the problem, find relief, and know when to alert your healthcare provider. Let's get started!

How is leg swelling medically evaluated?

When you visit your doctor with swelling in your lower extremities, the doctor will first want to know how long the swelling has been present and the frequency of your symptoms.  The doctor will also ask about your medical history and whether you are experiencing symptoms such as discomfort, redness, warmth, or changes in skin color.  Next, your doctor will likely perform a physical examination to check for signs of inflammation, infection, and any other visible conditions.  If a circulatory problem is suspected, your doctor may order tests, such as an ultrasound or venography x-ray.  

Is leg swelling down to the knee dangerous?

Most cases of leg swelling from the knee down are not dangerous and may improve with simple lifestyle changes and self-care measures. However, there are cases when leg swelling can signify a more serious problem, such as deep vein thrombosis (DVT), which requires immediate medical attention.

Should leg swelling persist after self-care steps or lifestyle modifications have been made, you should contact your doctor for an evaluation.

It is important to note should you experience any of the following symptoms; you should seek immediate medical attention:
  • Sudden and severe swelling of the legs.
  • Swelling that comes and goes but worsens at night.
  • Leg swelling accompanied by chest pain or shortness of breath.
  • Redness, warmth, or inflammation on the skin.

What are the 13 causes of leg swelling from the knee down?

There are several reasons why individuals experience leg swelling, and the underlying causes can vary from person to person.

Below are 13 of the most common causes to leg swelling from the knee down:

1. Sitting or Standing for Long Periods

Standing for Long Periods

Individuals that maintain a sedentary lifestyle or are required to remain stationary or standing at their job for extended periods may be at increased risk for leg swelling. When you sit or stand for extended periods, the blood begins to pool in your lower extremities, increasing pressure on your veins, which can lead to leg swelling.

2. Arthritis

Joints can become inflamed and swollen due to arthritis. This inflammation may cause fluid build-up, making it difficult for blood flow in your veins, leading to swelling in the lower legs.

3. Lymphedema

Lymphedema is a condition that occurs when the lymph nodes in your leg become blocked, and the lymphatic fluid accumulates in the lower extremities, leading to swelling in the legs. Lymphedema may result from cancer, treatment, surgery, medication, radiation therapy, or infection.

4. Heart Failure

Heart Failure

Heart failure is a serious condition that can develop when the heart does not pump blood efficiently. As a result, fluid builds up in your lower legs and feet, leading to edema or swelling of those tissues in the lower extremities. This condition causes significant discomfort and requires medical attention and management.

5. Liver disease

Liver disease is a condition that occurs when the liver cannot function properly. Due to a build-up of toxins in the body, fluids can accumulate in the lower legs and cause swelling below the knee.

6. Kidney Disease

Kidney disease is a condition that occurs when the kidneys are unable to filter waste and toxins from the blood. This can lead to a build-up of fluids in the tissues, including the lower legs and lower extremities.

7. Pregnancy


Many women experience swelling in their lower extremities during pregnancy due to the increased volume of blood and fluids in their bodies. This swelling is usually most pronounced in the third trimester and will typically resolve after birth.

8. Diabetes

People with diabetes are at an increased risk of developing lower extremity and leg swelling.

Diabetes leads to high blood sugar levels that can damage the veins and lead to diabetic nephropathy, which is the deterioration of kidney function.  Diabetic-related nephropathy can cause fluid accumulation and leg swelling.

9. Deep Vein Thrombosis (DVT)

Deep vein thrombosis is a serious condition that occurs when a blood clot forms in one of the deep veins in the body.  Symptoms of DVT include swelling, pain, redness, warmth in the leg, chest pain, and shortness of breath.

Should you experience any of the symptoms above, it is essential to contact your healthcare provider immediately.

10. Varicose Veins

Varicose Veins

Varicose veins occur when the valves in the veins that carry blood from your lower extremities back to your heart are not working correctly.  When this happens, blood can pool in these veins and cause them to swell, weakening the valves over time.  As the valves weaken, they cannot pump blood back up to the heart efficiently, known as venous insufficiency.

While venous insufficiency is most common in people who are obese or live a sedentary lifestyle, it is common amongst Americans.  An estimated 150,000 Americans are diagnosed with venous insufficiency every year.

11. Thyroid Disease

Thyroid disease increases the risk of developing swelling in the legs and feet.  The thyroid gland regulates the body's metabolism, and people with thyroid disease often have a slower metabolism and energy consumption rate.  As a result, thyroid disease can lead to a build-up of fluids in the body tissues, including the legs and feet.

12. Excessive Salt Intake


Excessive salt intake is another common cause of edema.  Sodium is a mineral found in salt, and it plays a vital role in the body's fluid balance.  When we consume too much salt, the body retains more water, leading to leg swelling and edema.

13. Low Protein Levels

Low protein levels can also lead to swelling in the lower legs.  Protein is essential for the body to manufacture enzymes and hormones that help to regulate fluid balance.  When the body doesn't have enough protein, it can't maintain fluid equilibrium, leading to edema and increased leg swelling below the knee.

How To Treat Swollen Legs From the Knee Down

There are many ways you can treat swollen legs from the knee down, depending on the underlying cause. Some of the most common at-home remedies include elevating your legs periodically, wearing compression stockings, regular exercise, monitoring salt intake, and maintaining a healthy weight.

In more serious cases, surgery is an option should the underlying cause be related to varicose veins, venous insufficiency, or lymphatic system deficiencies. Speak with your healthcare provider to determine the potential underlying cause.

Frequently Asked Questions

Why is only one ankle Swollen?

One ankle swollen

There are many reasons why one ankle may be swollen while the other is not. It could be a sign of an underlying medical condition, such as lymphedema or heart failure. It is important to see a doctor for determining the cause of the swelling so that appropriate treatment can be prescribed.

What foods can help reduce leg swelling?

The best foods to reduce swelling may vary depending on the underlying cause. However, some general tips include eating a healthy diet that is low in salt, drinking plenty of water to stay hydrated, eating plenty of fruits and vegetables, and avoiding processed foods.

It is also important to consult with a doctor or nutritionist to develop a personalized diet plan that will help reduce swelling in your legs.

How can I sleep with a swollen leg?

If you have swollen legs from the knee down, it is important to elevate your legs to keep the swollen area higher than the level of your heart. One way to do this is to place a pillow or two under your feet while you sleep.

You may also want to consider using a recliner instead of your bed. If the swelling is caused by a medical condition such as lymphedema, you may need to wear compression stockings or a compression bandage while you sleep.


There are many different causes of swollen legs from the knee down, and each one requires a different treatment approach. It is important to see a doctor if you are experiencing swelling in your lower extremities so that the underlying cause can be identified and treated.

Our team of vein specialists are board-certified and highly skilled in identifying venous conditions and underlying causes of leg swelling. They can also advise what type of treatment is best for treating it.


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