There are many causes of foot edema and painlessness, excluding sprains, other factors are related to heart, kidney, liver and varicose veins of lower limbs. If there is sudden swelling of the foot and there is no depression on pressure and the body has been healthy before, it is usually caused by varicose veins or prolonged standing, and it will improve with sufficient rest or by taking Mizarin. If there is a depression on pressure, for adults it is caused by nephritis, mostly accompanied by hypertension and proteinuria, which can be investigated in a targeted way. Weight loss group can cause malnutrition edema due to excessive dieting, which is accumulated gradually, and the edema will be gradually eliminated once normal diet is resumed. If you have had coronary artery disease and hypertension for many years and are relatively old, ankle swelling is a disease that has progressed to right kidney failure and requires standardized treatment.