What’s causing those swollen feet?

Perhaps you're just on your feet a lot, but the swelling also could signal a potentially serious condition.

Anyone can experience swollen feet from time to time. It's common — especially after walking or standing for long periods — and it's often remedied by resting and elevating those tired dogs.

Sometimes, however, swelling (also called edema) is a red flag for a more serious underlying problem, such as heart failure, deep vein thrombosis (a blood clot in a leg vein, kidney disease or cirrhosis of the liver.

Vascular causes

When you are on your feet a lot, gravity pulls blood into the veins of your legs, and some of the water in the blood enters the tissues of your legs and feet, causing them to swell. But there are also some conditions that can cause similar swelling because they affect the movement of fluids within the body.

Venous insufficiency. Valves in the veins of our legs keep blood from being pulled down by gravity and pooling in the leg veins. As we age, those valves age, too, and may function less efficiently. This is a common cause of swollen feet.

Phlebitis. This painful inflammation of the veins can cause swollen feet and also leg pain.

Deep-vein thrombosis. In this condition, blood clots form in the deep veins of the legs. The clots block the return of blood from the legs to the heart, causing swelling of the legs and feet. This can be very serious if it is not diagnosed and treated promptly: the blood clots can break loose and travel in the blood to the lungs, causing a condition called pulmonary embolism. This can cause breathlessness, pain with breathing, and even death. Usually, the clots occur in only one leg, and so just one leg is unusually swollen. While a new swelling of both legs and feet often is not serious, new swelling of just one leg is always something to bring to your doctor.

Heart failure. A failing heart does not pump as effectively as it should. As a result, blood in the leg veins that should be pumped back to the heart instead pools in the veins.

Liver disease. Some liver diseases can lead to low blood levels of a protein called albumin, which is made in the liver. Low albumin levels cause fluid in the blood to pass into the tissues, producing swelling not only of the legs and feet but also other parts of the body, such as the hands and face.

Kidney disease. Fluid can build up in the tissues if disease makes it hard for the kidneys to get rid of excess fluid in the body (one of the main functions of the kidneys).

Sometimes, swelling in the feet is the first clue that you have heart failure or liver or kidney disease, and your doctor needs to consider those possibilities. Your doctor will take a medical history and do a thorough physical examination that includes your heart and lungs. The doctor may order blood and urine tests, a chest x-ray, an electrocardiogram, or other tests.

Other causes

Sometimes swollen feet have causes that are not directly related to the flow of body fluids. For example:

Bone and tendon conditions. Several problems with the bones and tendons in your feet also can cause swelling, although (in contrast to the vascular causes) they also typically cause pain. Examples include fractures, arthritis, and tendinitis.

Problems with the skin and toenails. As we age, our skin thins. That makes skin more vulnerable to cuts, which then can become infected, causing swelling of the area near the wound. A cut on the foot can cause the whole foot to swell. Ingrown toenails that dig into the skin also can lead to sores and swelling.

Drug side effects. Some medications, such as calcium-channel blockers to treat high blood pressure, can also be the culprit.

What you should do

A little foot swelling is probably nothing to worry about. If you get off your feet and prop them up on a footstool, the swelling should disappear over several hours.

When should you call the doctor? Report your symptoms to your doctor if there's so much swelling that it leaves an indentation if you press your finger into it, or if it has developed suddenly, lasts for more than a few days, affects just one foot, or is accompanied by pain or discoloration of the skin.

Finally, don't make your own diagnosis. With so many potential reasons for swelling, it's important to let your doctor drill down to the cause, prescribe the treatment you need, and help you get back on your feet as soon as possible.

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