Foot edema, also known as soft tissue edema of the ankle, can be divided into three main causes: first, systemic factors, mainly in cardiac, hepatic and renal insufficiency, causing albumin leakage into the tissue interstitial space, vascular colloid osmolality decreases, resulting in extravasation of tissue fluid, often combined with systemic edema in many places. Second, inflammatory changes in the lower limbs, the most common causes such as dengue, cellulitis, etc., due to acute inflammatory changes in blood vessels or lymphatic vessels, causing increased vascular permeability, tissue fluid extravasation, resulting in subcutaneous tissue edema. Third, vascular factors, common for lower extremity venous thrombosis and varicose veins, due to increased venous pressure in the blood vessels, also caused by tissue fluid leakage of extravasation, causing lower extremity edema, once the ankle edema, should go to the regular hospital in a timely manner to the doctor, clear the cause of the edema and targeted treatment, and should be lifted up the affected limbs, reduce the ankle edema and improve the circulation of the lower extremities.