Edema is swelling caused by too much fluid trapped in the body's tissues. Edema can affect any part of the body. But it's more likely to show up in the legs and feet.

Medicines and pregnancy can cause edema. It also can be the result of a disease, such as congestive heart failure, kidney disease, venous insufficiency or cirrhosis of the liver.

Wearing compression garments and reducing salt in the diet often relieves edema. When a disease causes edema, the disease needs treatment, as well.

Edema occurs when tiny blood vessels in the body, also known as capillaries, leak fluid. The fluid builds up in nearby tissues. The leak leads to swelling.

Causes of mild cases of edema include:

• Sitting or staying in one position for too long.
• Eating too much salty food.
• Being premenstrual.
• Being pregnant.

Edema also can be a side effect of some medicines. These include:

• High blood pressure medicines.
• Nonsteroidal anti-inflammatory medicines.
• Steroid medicines.
• Estrogens.
• Certain diabetes medicines called thiazolidinediones.
• Medicines use to treat nerve pain.

Sometimes edema can be a sign of a more serious condition. Illnesses that can cause edema include:

• Congestive heart failure. Congestive heart failure causes one or both of the heart's lower chambers stop pumping blood well. As a result, blood can back up in the legs, ankles and feet, causing edema.

  Congestive heart failure can also cause swelling in the stomach area. This condition also can cause fluid to build up in the lungs. Known as pulmonary edema, this can lead to shortness of breath.

• Liver damage. This liver damage from cirrhosis can cause fluid to build up in the stomach area. and in the legs. This fluid buildup in the stomach area is known as ascites.
• Kidney disease. Kidney disease can cause fluid and salts in the blood to build up. Edema linked to kidney disease usually occurs in the legs and around the eyes.
• Kidney damage. Damage to the tiny, filtering blood vessels in the kidneys can result in nephrotic syndrome. In nephrotic syndrome, decreased levels of protein in the blood can lead to edema.
• Weakness or damage to veins in your legs. This condition, known as chronic venous insufficiency, harms the one-way valves in the leg. One-way valves keep blood flowing in one direction. Damage to the valves allows blood to pool in the leg veins and causes swelling.
• Deep vein thrombosis, also called DVT. Sudden swelling in one leg with pain in the calf muscle can be due to a blood clot in one of the leg veins. DVT requires medical help right away.
• Problems with the system in the body that clears extra fluid from tissues. If the body's lymphatic system is damaged, such as by cancer surgery, the lymphatic system might not drain well.
• Severe, long-term lack of protein. An extreme lack of protein in the diet over time can lead to edema.

The following increases the risk of edema:

• Being pregnant.
• Taking certain medicines.
• Having a long-lasting illness, such as congestive heart failure or liver or kidney disease.
• Having surgery that involves a lymph node.

If left untreated, edema can cause:

• Swelling that gets more and more painful.
• Problems walking.
• Stiffness.
• Stretched skin, which can itch.
• Increased risk of infection in the swollen area.
• Scarring between layers of tissue.
• Less blood flow.
• Less ability of the of arteries, veins, joints and muscles to stretch.
• Increased risk of skin ulcers.

To understand the cause of your edema, a health care provider will do a physical exam and ask about your medical history. This might be enough to figure out the cause. Sometimes, diagnosis might require blood tests, ultrasound exams, vein studies or others.

Mild edema usually goes away on its own. Wearing compression garments and raising the affected arm or leg higher than the heart helps.

Medicines that help the body get rid of too much fluid through urine can treat worse forms of edema. One of the most common of these water pills, also known as diuretics, is furosemide (Lasix). A health care provider can decide about the need for water pills.

Treating the cause of the swelling is often the focus over time. If edema is a result of medicines, for example, a care provider might change the dose or look for another medicine that doesn't cause edema.

Unless you're already seeing a health care provider for a condition such as pregnancy, you'll probably start by seeing your family provider.

Here's some information to help you get ready for your appointment.

What you can do

• Be aware of anything you need to do before the appointment. When you make the appointment ask if there's anything you need to do to prepare. For example, you might need to fast before certain tests.
• Write down your symptoms, including any that may seem like they have nothing to do with the reason for which you made the appointment. Note when the symptoms began.
• Make a list of your key medical information, such as other conditions you have. List medicines, vitamins and supplements you take, including doses.
• Make a list of questions to ask your provider. Bring something to write with or a recorder to get down the answers.
• Take pictures on your phone. If swelling gets much worse at night, it might help your health care provider to see how bad it gets.

For edema, some questions to ask might include:

• What are the possible causes of my symptoms?
• What tests do I need? How do I prepare for them?
• Is my condition long-lasting or temporary?
• What treatments, if any, do you recommend?
• I have other medical problems. How do I manage these conditions together?
• Do you have brochures or other printed material I can have? What websites do you recommend?

What to expect from your doctor

Your provider is likely to ask you questions, such as:

• Do your symptoms come and go, or are they always there?
• Have you had edema before?
• Are you short of breath?
• Does anything seem to make your symptoms better?
• Is there less swelling after a night's rest?
• Does anything make your symptoms worse?
• What kinds of foods do you regularly eat?
• Do you restrict salt and salty foods?
• Do you drink alcohol?
• Are you urinating as usual?