Nearly everyone will have some type of swelling that affects a part of their body at some point in their life. Swelling can be cause by many things, whether it be injury or illness. When it comes to swelling in your legs, it can be a result of either fluid buildup or retention, or from inflammation in injured or diseased tissues or joints. Many of the causes of leg swelling, such as an injury or prolonged standing or sitting, are common and are no cause for concern. However, there are times when leg swelling can indicate a more serious disorder. Learn more about the causes of leg swelling, treatment options available and when you should seek treatment.