Edema refers to visible swelling caused by a buildup of fluid within tissues. When an indentation remains after the swollen skin is pressed, this is called pitting edema. The effect may also be noticeable after taking off a tight shoe or stocking.
Anyone can have pitting edema, but because some causes are more dangerous than others, it is often a good idea to consult a doctor.
In this article, we describe who is at risk for pitting edema. We also explore accompanying symptoms, treatments, and prevention techniques.
This condition is most common in the lower body, particularly in the legs, ankles, and feet.
Swelling caused by edema will usually make the skin feel tight, heavy, or sore. Other symptoms depend on the cause, but they can include:
- tingling or burning sensations around the swelling
- pain and aching in the swollen areas
- skin that feels puffy or stiff
- skin that is warm or hot to the touch
- water retention
- unexplained coughing
- fatigue or decreased daily energy
- chest pain
- shortness of breath and difficulty breathing
People who experience chest pain, shortness of breath, or swelling in only one limb should seek immediate medical attention.
Pitting vs. non-pitting edema
Edema occurs when fluid that accumulates in tissues leads to swelling. When pressure is applied to a swollen area, it may leave a pit, in the skin.
In non-pitting edema, the skin will return to its swollen shape once the pressure has been removed.
A variety of factors can lead to pitting edema, including:
Alternatively, any of the following conditions may be responsible:
- high blood pressure
- psoriatic arthritis
- kidney problems
- lung diseases
- liver diseases
- deep vein thrombosis, which involves a blood clot, often in the leg
- chronic venous insufficiency, which occurs when the veins are inhibited
- complications of the heart valve
- congestive heart failure
Pitting edema may also be a side effect of medications such as:
Pitting edema can affect anyone, though certain factors can increase a person's risk.
In most cases, a doctor should determine the cause of pitting edema and, if necessary, refer a person to a specialist.
Some accompanying symptoms require urgent care. Anyone experiencing shortness of breath, difficulty breathing, chest pain, or swelling in a single limb should seek immediate medical attention.
When leg pain and swelling persist after a person has been sitting for several hours, this may indicate deep vein thrombosis. This occurs when a blood clot develops deep in the leg. Anyone who suspects this should seek urgent medical care.
Pitting edema during pregnancy
Pregnancy can cause pitting edema, and it usually resolves as the pregnancy ends.
However, it is a good idea to discuss every new symptom with a doctor, who can test to rule out serious conditions linked with edema, such as very high blood pressure or preeclampsia.
Pitting edema is often diagnosed with a physical exam. The doctor may apply pressure to the swollen skin for about 15 seconds to check for lasting indentation.
Because some associated conditions are more dangerous than others, it is important to find the underlying cause of the edema. This may require thorough testing. The edema will usually resolve once the cause has been treated.
To properly identify the underlying cause, a doctor may take a detailed medical history and ask about medications. They may then refer the person to a doctor who specializes in issues concerning the veins or circulatory system.
Tests that can aid in a diagnosis of pitting edema include:
- a physical exam
- imaging tests, such as X-rays, which can show fluid retention and problems in the lungs
- blood tests
- urine tests
- an echocardiogram, which is an ultrasound scan of the heart
Pitting edema is classified based on the depth and duration of the indentation. The following scale is used to rate the severity:
Grade 1: The pressure applied by the doctor leaves an indentation of 0–2 millimeters (mm) that rebounds immediately. This is the least severe type of pitting edema.
Grade 2: The pressure leaves an indentation of 3–4 mm that rebounds in fewer than 15 seconds.
Grade 3: The pressure leaves an indentation of 5–6 mm that takes up to 30 seconds to rebound.
Grade 4: The pressure leaves an indentation of 8 mm or deeper. It takes more than 20 seconds to rebound.
Understanding the severity of edema can help a doctor to identify the underlying cause and best course of treatment.
This involves addressing the underlying cause of the edema. A range of treatments correspond with the range of causes, but common methods include:
- elevating the swollen limbs above the level of the heart
- wearing compression stockings to encourage circulation. Compression stockings are available for purchase online.
- undergoing vascular surgery
- increasing blood protein levels
- taking diuretics to flush out excess fluid
When the underlying cause has been successfully treated, edema is unlikely to recur.
Some adjustments to lifestyle and diet can reduce the likelihood of developing edema, particularly if a person has a high risk.
These changes may include staying active, avoiding sitting or standing for long periods, and doing gentle exercises to reduce swelling.
Pitting edema is a common symptom. It is usually not a cause for concern in itself, but many underlying conditions require treatment, sometimes urgently.
Edema should not cause any long-term complications. After working with a doctor, many people find lasting relief from the symptom.