Causes of swollen feet are mainly considered to be bone and joint diseases, lower limb vascular lesions, trauma, tumors or cardiac and renal insufficiency. 1. Osteoarthritic diseases: abnormal lesions in ankle or toe joints, such as joint inflammation or degenerative diseases, gouty arthritis, etc., can cause localized swelling and pain, and can involve the whole foot to show swelling. Usually accompanied by obvious pain. 2. Lower extremity vascular lesions: abnormal lesions of the lower extremity blood vessels, such as varicose veins or deep vein thrombosis, etc., can easily affect the blood reflux, which can cause swelling of the feet. 3. Trauma: If the position of the foot is affected by the impact of external force, which leads to local injury, it may directly lead to the increase of exudate, which leads to swelling of the foot, and may be accompanied by painful symptoms. 4. Tumor: If there is tumor growth in the foot area, such as bone tumor, the tumor will easily produce occupying effect and press the surrounding tissues, so it will trigger the symptoms of swollen feet. 5. Cardiac and renal insufficiency: For patients with cardiac and renal insufficiency, it is easy to affect the circulatory system, which leads to the limitation of blood and tissue fluid reflux in the lower limbs, thus triggering the phenomenon of swollen feet, such as nephrogenic edema and cardiac edema, etc. If the symptoms of swollen feet are more serious, it may cause pain. If the symptoms of swollen feet are more serious, you need to consult a doctor in a timely manner, first check the cause of the disease, under the guidance of professional physicians targeted treatment.