Lymphedema, or lymphatic obstruction, is a long-term condition where excess fluid collects in tissues causing swelling (edema). Lymphedema commonly affects one of the arms or legs. In some cases, both arms or both legs may be affected. Some patients might experience swelling in the head, genitals, or chest. Lymphedema is incurable, but with the right treatment, it can be controlled. Experts believe lymphedema is primarily caused by genetic mutation.
Lymphedema affects the lymphatic system. This system has three main functions: draining excess tissue fluid, fighting infection, absorbing fats. A disruption to the lymphatic system can undermine its ability to drain fluid properly. As a result, the excess fluid can build up in parts of the body. Lymphedema increases the risk of infection and other complications because the lymphocytes cannot reach parts of the body where swelling occurs.
Christian Nordqvist, What is Lymphedema?, Medical News Today (updated Dec. 20, 2017), https://www.medicalnewstoday.com/articles/180919.php