The causes of swelling of the back of the foot are as follows: 1. idiopathic edema, idiopathic edema is edema for which no clear cause can be found, which is more common in life, and often occurs after prolonged standing or eating too much salt. The swelling of the dorsum of the foot can be caused by hypoproteinemia caused by proteinuria. 3, heart disease, heart disease patients, especially those with cardiac insufficiency, will experience swelling of the dorsum of the foot due to a decrease in the amount of blood return caused by heart failure. 4, liver disease patients, liver function problems lead to a decrease in protein synthesis in the body, and swelling of the dorsum of the foot can occur after hypoproteinemia. 5, Malnutrition or endocrine system diseases, such as hypothyroidism, can lead to swelling of the back of the feet.