Why is my ankle swelling?

Many possibility: There are many possibilities. If it is only one ankle think of ankle issues i.E weak ligaments, poor foot alignment these an be addressed by a podiatrist. Venous disease can cause swelling but more than the ankle is usually involved. Ask you md for further aid in deciding where to go.

Several possiblities: Injury is one. However in absence of injury, other common causes are venous insufficiency, lymphedema, many types of arthritis and even infection as well as cardiovascular conditions. Does elevation help? If so, that's good but if this is a chronic condition, have it checked by physician.

Many possibilities: Venous insufficiency, hypertension, kidney or cardiac issues, side effect of medications, h/o of ankle injury. There are many possibilities and hence a history and physical by your internist is a good idea.

Many possibilities: Some causes of swelling of the ankles can include systemic problems such as hypertension, gout, and problems with the kidneys and localized issues such as arthritis, infection, lymphatic obstruction, blood clots, varicose veins, trauma (fracture, sprain, and tendonitis) and side effects to medication. Have it evaluated by a professional and get the appropriate treatment.