Oedema (formerly known as dropsy or hydropsy) is observable swelling from fluid accumulation in body tissues. Oedema most commonly occurs in the feet and legs, where it is referred to as peripheral oedema. The swelling is the result of the accumulation of excess fluid under the skin in the spaces within the tissues.All tissues of the body are made up of cells and connective tissues that hold the cells together.edema most commonly occurs in the feet and legs, where it is referred to as peripheral oedema. The swelling is the result of the accumulation of excess fluid under the skin in the spaces within the tissues.