The swelling may be widespread or confined to one or part of a limb. But the swelling is often in the feet and legs. However, people who are required to stay in bed for long periods (for bed rest) sometimes develop swelling in the buttocks, genitals, and the back of the thighs. Also, women who lie on one side only may have a lump in the breast on which they lie. Rarely, the hand or arm may be swollen.
Sometimes a limb swells suddenly. Swelling often appears slowly, beginning with weight gain, swollen eyes upon waking in the morning, and tight shoes at the end of the day. The swelling may appear so gradually that patients do not notice it until it becomes large. Sometimes patients feel tight or full. Other symptoms may be present depending on the cause of the swelling and may include shortness of breath or pain in the affected limb.
Swelling that occurs all over the body has different causes than swelling that is limited to one or part of a limb.
The most common causes of extensive swelling are:
Kidney disorders (particularly nephrotic syndrome)
All of these disorders cause fluid retention, which is the cause of the swelling.
There is another reason for swelling in the legs, which is the accumulation or stagnation of blood in them. Many people who are obese, middle-aged, or older people usually have a small amount of swelling at the end of the day due to pooling or stagnation of blood. This swelling usually disappears in the morning. Blood can also pool in the legs if the valves in the veins are enlarged or damaged (chronic venous insufficiency), as may occur in people who have had blood clots in the legs. In these people, the swelling usually does not go away overnight.
Many women usually have some swelling during the later stages of pregnancy. But women who have significant swelling, especially if the swelling also includes the hands and face and is accompanied by high blood pressure, may have preeclampsia, which can be dangerous.
The most common causes of swelling that is limited to one or part of a limb are:
A blood clot in a deep vein in a limb (deep vein thrombosis)
Skin infection (cellulitis)
Several disorders increase the risk of blood clots developing in the veins. These clots occur most often in a vein in the legs, but sometimes they occur in a vein in the arm. Blood clots in a vein can be dangerous if the clot breaks loose, travels to the lungs, and blocks an artery there (called a pulmonary embolism).
Cellulitis usually causes swelling of the skin on only part of the limb. In far fewer cases, infection deep in the skin or in the muscles can cause swelling of the entire limb.
A lymphatic vessel blockage (as occurs in lymphedema) is a less common cause. Lymph vessels, which are found throughout the body, help drain fluid from tissues. If a tumor is pressing on the lymph vessels or when surgery is performed to remove some of the lymph vessels or nodes (for example, when lymph nodes are removed from the armpits in women with breast cancer), the limb can swell. In many tropical countries, some parasites can block lymph vessels and cause swelling (lymphatic filariasis).
Sometimes, an allergic reaction causes swelling around areas such as the mouth (angioedema). Angioedema can also be a genetic disorder in which swelling appears and disappears at irregular intervals.
Although swelling may appear as a slight irritation, especially if it does not cause discomfort and disappears if the patient sleeps, it can be a symptom of a serious disorder. The following information can help people determine the need for a doctor’s visit and consultation, and to anticipate what will happen during the examination and evaluation process.
Some symptoms and characteristics are cause for concern in people with swelling. It includes:
Appearance or sudden onset
Only one leg is swollen
Severe pain or tenderness
shortness of breath
coughing up blood.
When should you see a doctor?
People who develop warning signs should see a doctor immediately. People without warning signs, who have a history of heart, lung or kidney disease, or who are pregnant, should see a doctor within a few days. Other people who do not have warning signs should schedule a doctor’s appointment when appropriate. Usually a delay of a week or so is not harmful.
What will the doctor do?
The doctor first asks a few questions about the patient’s symptoms and medical history. Then the doctor performs a clinical examination. What he finds during the medical history and physical examination often indicates the cause of the swelling, and the tests that may need to be done.
Doctors ask about the location and duration of the swelling, and the presence and degree of pain or discomfort. Women are usually asked if they are pregnant, or if the swelling appears to be related to their menstrual periods. Doctors also ask if the person has any disorders (for example, heart, liver, or kidney disorders) or is taking any medications (for example, minoxidil, nonsteroidal anti-inflammatory drugs, or ACE inhibitors). Angiotensin I (ACE) or amlodipine and other calcium channel blockers) are known to cause swelling. They also ask how much salt is used in cooking and at the table, because excess salt can make swelling worse, especially in people with heart or kidney disorders.
They look for symptoms that may indicate the cause of the swelling. For example, people with heart failure may develop shortness of breath during exertion, or may wake up at night with shortness of breath. People with easy swelling and bruising may also have a liver disorder, and people who have recently had surgery or had a cast on their leg may have deep vein thrombosis.
Doctors may ask people with long-lasting swelling to record their daily weight so that increases in swelling are quickly detected.
During the physical examination, doctors pay special attention to the area of swelling, but closely examine the person for other signs as well. Doctors also listen to the heart and lungs with a stethoscope, because swelling may be a sign of a heart disorder.
For most people with extensive swelling, blood tests are done to evaluate the function of the heart, kidneys, and liver. Urinalysis is also usually done, to check for large amounts of protein, which can indicate nephrotic syndrome or preeclampsia in pregnant women. Other tests are done based on the suspected cause. For example, in people with isolated leg swelling, doctors may do an ultrasound to look for a blockage in a vein in the leg.
The specific causes are treated (for example, anticoagulants [blood thinners] are given to people with blood clots in the legs). Any medications that cause swelling are also stopped or changed if possible.
Since the swelling itself is not harmful, doctors do not give people water pills (diuretics) unless there is a need to treat the cause of the swelling (such as heart failure). However, simple general measures such as sitting with the legs elevated or limiting the amount of salt in the diet sometimes help reduce swelling.