What Causes Lymphedema in the Legs?

When the body’s lymphatic system does not work properly, fluid can build up in the tissues just under the skin. This buildup causes swelling, most often in the legs.

The medical term for this type of swelling is lymphedema. Lymphedema is a long-term condition, but it can be treated and managed with proper care.

What is the lymphatic system?

The lymphatic system is part of your immune system. It helps:

Remove waste from the body
Fight infection
Keep fluid levels balanced

It is made up of tiny vessels, lymph nodes, and organs that carry a clear, protein-rich fluid called lymph throughout the body.

The lymphatic system works a lot like the blood vessels in your body. Just as blood flows through arteries and veins, lymph flows through lymphatic vessels.

What causes lymphedema?

Lymphedema happens when the lymphatic system is damaged, blocked, or underdeveloped. When lymph fluid cannot drain properly, it builds up and causes swelling. Common causes include:

Cancer or cancer treatments (such as surgery or radiation)
Injury or trauma
Infections
Obesity
Certain medications
Genetic or inherited conditions

Obesity can increase pressure on the lymphatic system, making it harder for fluid to drain. Over time, lymphedema can also cause fat buildup and further damage to lymph vessels, creating a cycle where symptoms continue to worsen if untreated.

Lymphedema can start at different ages, depending on the cause.

Where does lymphedema usually start?

Lymphedema often begins before swelling is visible. Early symptoms may include:

A feeling of heaviness
Aching or discomfort
Tingling or tightness in the leg

As the condition progresses, swelling may come and go. In early stages, pressing on the swollen area may leave a dent in the skin, called pitting. Raising the leg can temporarily reduce swelling during this stage.

Early treatment is essential. Over time, elevation may no longer help as the skin and tissues can become thick and scarred, causing swelling that is more permanent and harder to control.

Lymphedema can increase the risk of skin infections. With proper treatment, however, the progression of lymphedema can often be slowed or stopped.

Lymphedema versus other causes of leg swelling

Leg swelling can happen for many reasons. It is common during pregnancy and in adults over 65. Swelling can also be caused by problems with:

The heart
Blood vessels
Liver
Kidneys

Sitting for long periods or wearing tight socks can also cause temporary leg swelling.

Lymphedema is another cause of leg swelling and is sometimes overlooked. It can be confused with chronic venous insufficiency, a condition in which blood does not flow well back to the heart. Chronic venous insufficiency is common in older adults, especially those over 70.

Because treatment differs, it’s important to get the correct diagnosis.

What Is the treatment for lymphedema?

Treatment focuses on reducing swelling and preventing complications.

The most common treatment is complete decongestive therapy, which is considered the gold standard, especially in early stages. This therapy is noninvasive and includes: