What are the causes of swelling of the ankles and feet?

A few things. Excess dietary sodium can cause fluid retention, which can explain swelling in the foot, ankles and legs. Prolonged sitting or standing in place may cause swelling. It can also be due to other medical issues as well: congestive heart disease, htn, diabetes, uremia and many other issues.. Discuss this with your doctor.
Swelling. There are many causes of swelling in the ankles and feet. Venous problems, lymphatic problems, effects of gravity, some medications etc. See a podiatrist for a thorough lower extremity history and physical examination and report of findings to help you solve this problem.