Accumulation of fluid can cause swelling of the feet, ankles and legs--a condition known as peripheral edema. Pain may accompany the swelling. In some cases, painless swelling might develop in the feet and ankles of the elderly, notes Medline Plus. Leg swelling can occur in all parts of the limb, from the feet to the calves and thighs. Causes of leg swelling range from the normal force exerted by gravity on a healthy individual to trauma and serious illnesses.
Venous Insufficiency
Venous insufficiency--a condition in which faulty veins fail to move blood out of the legs--can cause leg swelling. Dr. John W. Ely and colleagues, in a review article published in 2006 in "The Journal of the American Board of Family Medicine," note that venous insufficiency remains a common cause for both unilateral--affecting one leg--and bilateral--affecting both limbs--leg swelling in the United States.
Blood clotting in the deep veins of the legs--known as deep vein thrombosis--constitutes the other common cause of unilateral leg swelling in the U.S. population, according to Dr. Ely and colleagues. Leg swelling caused by deep vein thrombosis can be painful. Tenderness and redness may accompany the swelling, and the skin may feel warm to the touch, notes the Merck Manual for Healthcare Professionals.
Heart Failure
Heart failure--the inability of the heart to pump an adequate amount of blood through the body--can cause painless leg swelling. The swelling occurs symmetrically in both legs. Poking the leg with a finger leaves an indentation, notes the Merck Manual. This type of swelling is known as pitting edema. Medline Plus notes liver failure and kidney failure can cause leg swelling, due to excessive amounts of fluid in the body.
Gravity and Inactivity
Common causes for leg swelling include standing for long periods of time, or sitting without moving, such as during long trips in automobiles or in aircraft. In both cases, gravity plays a role in causing blood to pool in the legs. Dr. Ely and colleagues list obesity as one of the common causes of leg swelling in the U.S.
Menstrual Periods and Pregnancy
Some women experience leg swelling during their menstrual periods. A pregnant woman may develop swollen feet. If the swelling becomes excessive, that might signal the existence of a serious condition known as pre-eclampsia. A pregnant woman whose feet swell excessively should notify her doctor immediately.
Burns and Trauma
Ankle or foot trauma can cause swelling in those areas. Leg swelling might develop after foot or leg surgery. Medline Plus mentions burns, infections, insect bites and malnutrition as other possible causes of leg swelling.
References
- "The Journal of the American Board of Family Medicine"; Approach to Leg Edema of Unclear Etiology; John W. Ely, M.D., M.P.H., et al.; March-April 2006
- Medline Plus: Foot, Leg, and Ankle Swelling
- University of Maryland Medical Center: Foot, Leg, and Ankle Swelling--Overview
- Merck Manual for Healthcare Professionals: Lower-Extremity Edema During Late Pregnancy
- Merck Manual for Healthcare Professionals: Approach to the Cardiac Patient--Edema
