The common causes of left leg and ankle swelling are trauma, gouty arthritis, osteoarthritis, lower extremity venous thrombosis and so on. 1. Trauma: If the ankle has been traumatized, the inflammatory reaction will also cause edema, usually acute injury needs to be iced, and if there is a wound breakout, it needs to be cleansed. 2. Gouty arthritis: patients with gout, if the body’s uric acid level is not well controlled, it is easy to cause acute attacks of gout, joint pain and swelling. 3. Osteoarthritis: This is a chronic joint disease characterized by degeneration, destruction of articular cartilage and osteophytes, which can cause local pain, swelling and stiffness when symptoms worsen. 4. Lower extremity venous thrombosis: due to various reasons of poor blood return to the lower extremities, it can show localized pain and swelling, and there may also be obvious skin bruising and purple. Causes of left leg and ankle swelling more causes, may also be related to varicose veins of the lower extremities, cardiac and renal insufficiency and other diseases, if the symptoms do not get better after resting, it is recommended to go to the hospital in a timely manner to find out the cause of the disease, targeted treatment.