Oedema (U.S. edema)[1] is dropsy. It was usually called dropsy until about the middle of the 20th century.
It is a medical condition, and a sign or symptom. It is swelling caused when fluid leaks out of the body's capillaries into the tissues. The fluid builds up and gets trapped in the tissues around the leaking blood vessels.[2] This causes swelling. If there is enough swelling, oedema can be seen from outside of the skin.
Oedema can happen in any part of the body However, it is easiest to see in the arms and legs, including the hands, ankles, and feet.[2] Oedema in the arms and legs is called peripheral oedema.[3]
Pulmonary oedema is fluid in the lungs.[4] Pulmonary oedema is dangerous because having fluid in the lungs makes breathing difficult. If pulmonary oedema gets bad enough, a person can drown in the fluid.[5]
Oedema in the abdomen is called ascites.[6]