Edema: Causes, Symptoms and Prevention


Edema is a condition characterised by swelling in various parts of the body and is caused by fluid retention within the tissues. It most commonly occurs in the lower limbs (known as peripheral edema), particularly the lower legs, ankles and feet, but can occur anywhere on the body. When it occurs around the lungs it is known as pulmonary edema and can be potentially life-threatening.


There are many possible causes of edema, including pregnancy, too much salt in the body,heart, kidney or liver problems and lymph node issues. Localised damage or related trauma can also result in edema, for example sunburn, being on your feet a lot in hot weather, varicose veins, insect bites, and dermatitis. Although not immediately obvious as a circulatory condition, edema is in fact often the result of poor blood flow as reduced circulation in or around the kidneys causes these organs to retain salt and water, which is then held within the body, producing the characteristic swelling.


Often diagnosis will include the application of pressure to a small part of the swollen area to see if the resulting indentation remains visible for a considerable time and this is known as pitting edema.


There are several measures which can be taken to improve the condition, such as reducing salt levels in the diet (which is beneficial for health in general, especially high blood pressure), taking diuretic tablets to remove excess water and salt from the body, raising the legs when seated or the use of compression stockings. Compression stockings are effective in both the treatment and prevention of peripheral edema, with knee-high varieties generally the best option. For mild cases over-the-counter stockings will be sufficient, whilst more serious edema may require prescription stockings. They help by improving the circulation which will in turn improve blood flow to the kidneys, thus reducing water and salt retention within the body.