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Causes - Lymphoedema

There are 2 types of lymphoedema, primary and secondary lymphoedema. They have different causes.

Primary lymphoedema

The cause of primary lymphoedema is genetic. Changes (mutations) in certain genes can affect the development of the lymphatic system.

This means the parts of the lymphatic system that drain fluid do not work well.

Primary lymphoedema often runs in families. But not every child born to someone with the condition will develop it.

Secondary lymphoedema

Secondary lymphoedema develops in people when their lymphatic system is damaged.

The following sections describe the most common causes.

Surgery for cancer

Some cancer treatments can include surgery to remove sections of the lymphatic system.

Your surgeon will try to limit damage to your lymphatic system. But sometimes this is not possible. There's a high risk of having lymphoedema if you need to have some lymph nodes removed.

Lymph nodes are pea-sized lumps of tissue that contain white blood cells. They help remove bacteria, viruses and other causes of infection from your body.

Some of the common cancers where this happens are:


Radiotherapy uses controlled doses of radiation (high energy) to destroy cancerous tissue. But it can also damage healthy tissue.

If there are cancerous cells in your lymphatic system, you may need radiotherapy to destroy them. This treatment can damage the lymphatic system.


Infections such as cellulitis and lymphatic filariasis can cause lymphoedema.

Cellulitis is a bacterial infection of the dermis (deep layer of skin). Severe cellulitis can damage the tissue around the lymphatic system.

Lymphatic filariasis is a parasitic disease caused by microscopic worms. The adult worms live in the human lymphatic system and block lymph drainage.

Lymphatic filariasis is a common cause of lymphoedema worldwide. But it's not a high risk in Ireland.


Conditions where your body tissue is red and swollen can damage the lymphatic system.

Common conditions that can cause lymphoedema include:

Venous diseases

Venous diseases are diseases that affect the flow of blood in the veins. They can cause lymphoedema in some people.

Abnormal or damaged veins can cause fluid to overflow from the veins into the tissue spaces. The excess fluid becomes too much for the lymphatic system to drain.

Some venous diseases that can cause lymphoedema include:


Obesity can cause secondary lymphoedema.

People who are obese have a higher risk of having swollen body parts. The reason for this is not clear. The extra fatty tissue may affect the flow of fluid in the lymphatic channels.

Weight loss is an important part of treatment. Even starting to lose weight can make a big difference.

Check your BMI on the SafeFood website

Trauma and injury

In rare cases, accidental injury to the lymphatic system causes lymphoedema.

For example, it sometimes happens after a road traffic accident. The extensive bruising or soft tissue loss leads to lymphoedema.


Movement and exercise help lymph drainage. Muscle activity around the lymphatic vessels massages fluid into and along the vessels.

Reduced movement can lead to lymphoedema. This is because the fluid in the lymphatic system does not flow properly.

You may be at risk if you have limited mobility for a long time because of an illness, nerve damage or arthritis.

Content supplied by the NHS and adapted for Ireland by the HSE

Page last reviewed: 25 March 2021
Next review due: 25 March 2024

This project has received funding from the Government of Ireland’s Sláintecare Integration Fund 2019 under Grant Agreement Number 123.