Thanks for contacting with your health concern 1. leg swelling [peripheral edema] can be caused either by the problem with the circulatory system, lymphatic system or the kidneys [since there is no history of injury thus causes of swelling related with inflammation are not listed] and since DVT is excluded thus the following approach is advisable: . As the swelling occurred suddenly and without any apparent reason seek immediate medical care so that your doctor can diagnose the underlying problem, till then: - salt restricted diet - elevation of legs when lying down 2. Other causes like premenstrual syndrome, hypothyroidism, nutritional deficinecies can also be searched for.