Some causes of swelling and pain in a leg can include deep vein thrombosis, gout and knee bursitis. Many conditions can cause these symptoms in different parts of the legs, such as different types of arthritis, sprains or an infection. In particular, rheumatoid arthritis is an autoimmune inflammatory condition in which there is swelling in the affected leg joints and pain may be present, as noted by Mayo Clinic.
Rheumatoid arthritis can affect the feet joints in its early stages. With the progression of time, it affects other larger joints, such as the knees and ankles. Rheumatoid arthritis can affect other joints of the body, including the wrists, hips and shoulders, states Mayo Clinic. Gout is another form of arthritis that causes severe pain and inflammation in the leg joints, including the toes, knees and ankles.
Deep vein thrombosis occurs when there is the formation of a blood clot in deep veins of the legs, states WebMD. The main symptoms experienced with this condition are pain and inflammation. This serious condition can lead to pulmonary embolism if the blood clot breaks off and travels to the lungs.
Knee bursitis occurs when there is swelling in the bursa, a sac filled with fluid and functions as a cushion between bones and other structures of the knee. The condition also causes joint pain. A Baker's cyst can cause pain and swelling at the back of the knee, as noted by the National Institutes of Health's MedlinePlus.