Subcutaneous edema is caused by fluid filling the spaces between blood vessels. There are many causes of subcutaneous edema, which are divided into local subcutaneous edema and generalized subcutaneous edema. Localized subcutaneous edema may be caused by inflammation of veins or lymphatic tissues, or it may be caused by external force on the skin, and it is only edema in a certain area, not generalized, which is not serious and can be treated by oral anti-inflammatory drugs and topical medications. Causing generalized edema may be heart disease, kidney disease, hypertension, liver cirrhosis, kidney failure, poisoning, etc., all of which are more serious diseases. Generalized edema is mostly caused by lesion of an organ or endocrine disorder, and needs timely treatment. Some malignant diseases, such as liver cancer, kidney cancer, stomach cancer and other cancers, can also lead to generalized edema in patients. Besides, women who are pregnant may also develop generalized edema due to hormonal changes in their bodies, but the edema will disappear with the termination of the pregnancy period.