Your lymphatic system is crucial to keeping your body healthy. It circulates protein-rich fluid throughout your body, collecting bacteria, viruses, and waste products. Your lymphatic system carries these through your lymph vessels, which lead to lymph nodes. Lymphedema occurs when your lymph vessels are unable to adequately drain lymph fluid from your arm, leg, or another body part.

Causes of primary lymphedema

Primary lymphedema is a rare, inherited condition caused by problems with the development of lymph vessels in your body. Primary lymphedema occurs most frequently in women and usually affects the legs, rather than the arms. Specific causes of primary lymphedema include:

  • Milroy disease (congenital lymphedema) This is an inherited disorder that begins in infancy and causes a malformation of your lymph nodes, leading to lymphedema.
  • Meige disease (lymphedema praecox) This hereditary disorder causes lymphedema in childhood or around puberty. It causes your lymph vessels to form without the valves that keep lymph fluid from flowing backwards, making it difficult for your body to properly drain the lymph fluid from your limbs.
  • Late-onset lymphedema (lymphedema tarda) This occurs rarely and usually begins after age 35.

Causes of secondary lymphedema

Any condition or procedure that damages your lymph nodes or lymph vessels can cause lymphedema. Causes include:

  • Surgery can cause lymphedema to develop if your lymph nodes and lymph vessels are removed or severed. For instance, surgery for breast cancer may include the removal of one or more lymph nodes in your armpit to look for evidence that cancer has spread. If your remaining lymph nodes and lymph vessels can't compensate for those that have been removed, lymphedema may result in your arm.
  • Radiation treatment for cancer can cause scarring and inflammation of your lymph nodes or lymph vessels, restricting flow of the lymph.
  • Cancer cells can cause lymphedema if they block lymphatic vessels. For instance, a tumor growing near a lymph node or lymph vessel could become large enough to obstruct the flow of the lymph fluid.
  • Infection can infiltrate your lymph vessels and lymph nodes, restricting the flow of lymph fluid and causing lymphedema. Parasites also can block lymph vessels. Infection-related lymphedema is most common in tropical and subtropical regions of the globe and is more likely to occur in undeveloped countries.
  • Injury that damages your lymph nodes or lymph vessels also can cause lymphedema.

    Symptoms may includea heavy swollen limb or localized fluid accumulation in other body areas, restricted range of motion in an arm or leg, including the head or neck, discoloration of the skin overlying the lymphedema, recurring infections in your affected limb, hardening and thickening of the skin where the lymphedema is located also known as fibrosis. Swelling ranges from mild, hardly noticeable changes in the size of your limb to extreme swelling with abnormal skin folds that that can make it impossible to use the affected arm or leg.

    Lymphedema should not be confused with edema arising from venous insufficiency, which is not lymphedema. However, untreated venous insufficiency can progress into a combined venous/lymphatic disorder which is treated the same way as lymphedema (see Treatment below).

    Learn more about lymphedema:
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