Edema refers to the presence of fluid in a region of the body, in the skin, or other mucous membranes and tissues. It is an excess or an accumulation of a serous fluid.
In fact, edema is a symptom that manifests itself in a very large number of affections, very different from each other: inflammation, circulatory disorder ... and whose treatments will be very different.
Edema is very often a symptom of inflammation. Other major signs of inflammation are heat, redness, and pain. Example: In case of nasopharyngitis, in addition to having a sore throat, the patient often has a slight edema in the pharynx.
In case of joint trauma, an inflammatory reaction occurs. There is of course pain in the joint, but also an increase in its volume (related to edema), redness, and the joint is hot. This is also evident in inflammatory rheumatism.
Inflammation can have different origins, such as an infectious disease, an allergy, an autoimmune disease, a tumor, etc.
In case of strong allergic reaction and Quincke 's edema, for example, the throat is swollen and may strongly impede the passage of air. In case of asthma, the thickness of the small bronchi increases, due to local edema.