Causes of Swelling in the Feet

Swelling, or edema, in the ankles and the feet could be due to serious health problems. A variety of causes of lower extremity swelling should be investigated by a physician to prevent complications associated with an underlying and treatable health disorder.
Kidney Failure
Individuals with intermittent or persistent swelling in the ankles and feet may be experiencing kidney failure due to uncontrolled diabetes, dehydration, severe high blood pressure, obstruction that blocks urine flow and autoimmune disorders. Other causes of kidney failure include hemorrhage, shock, sepsis (infection in the bloodstream), injury or severe trauma and major surgery. Swelling in the lower extremities occurs when the kidneys cannot keep up with filtering waste products from the body, causing fluid retention. Acute kidney failure may be life-threatening.
Poor Circulation
Vascular disease, such as peripheral artery disease and severe varicose veins, can lead to ankle and foot swelling, especially with prolonged standing or sitting. Causes of peripheral artery disease include smoking, plaque buildup from high cholesterol, diabetes and high blood pressure. Poor circulation from disease in the veins is known as chronic venous insufficiency. Other symptoms include intermittent pain with walking, feelings of "heaviness" in the extremities and coolness to touch in the feet. In severe cases the feet can become a dusky color indicating impaired blood flow that could indicate a clot has formed from pooling (stagnation) of blood flow.
Thrombophlebitis
Inflammation of the superficial or deep veins in the legs can cause swelling. Foot and ankle swelling brought about by thrombophlebitis is the result of trauma to the vein, often from a direct blow. Individuals with blood clotting disorders can have thrombophlebitis. In addition to swelling, the condition causes pain to the touch, redness and warmth over the affected area.
Lifestyle
Wearing ill fitting shoes and socks with elastic that constrict circulation can cause the feet and ankles to swell. Other lifestyle factors causing fluid retention and impaired circulation in the lower extremities include consuming too much salt, obesity and lack of exercise. Diabetics are especially prone to poor circulation, making proper footwear a primary focus to prevent swelling, which can lead to ulcers and amputation.
Cellulitis
Cellulitis is caused by a bacterial infection that can affect the skin of the legs and ankles. Swelling in the feet and ankles accompanied by warmth, fever, blistering, rash and pain require evaluation and treatment that should not be delayed. Infection from cellulitis can spread throughout the body, causing serious illness.
Medications
Commonly used medications to treat high blood pressure, known as calcium channel blockers, can cause ankle and foot swelling that is not dangerous. Swelling can extend to the thighs or affect the entire leg. Hormones and steroids, as well as antidepressants, known as MAO inhibiors, also can cause fluid retention with resultant foot and ankle swelling.

If patients have other symptoms or discomforts besides feet swelling such as fatigue, loss of appetite, nausea, vomiting, shortness of breath, chest pain, it is recommended to see a doctor and seek proper treatment as soon as possible according to the underlying cause.