What Is It, Causes, Grading, Diagnosis, Treatment, and More
Author: Ahaana Singh
Illustrator: Abbey Richard
What is pitting edema?
Pitting edema occurs when excess fluid builds up in the body, causing swelling; when pressure is applied to the swollen area, a “pit”, or indentation, will remain. Although it can affect any part of the body, pitting edema usually occurs in legs, feet, and ankles. Most cases of pitting edema are dependent or peripheral. Dependent edema occurs as a result of gravity pulling blood down, which can ultimately result in tissue swelling, most often affecting the legs and feet. Peripheral edema, on the other hand, occurs as a result of fluid retention in the peripheral tissues, such as the hands, legs, and feet.
What causes pitting edema?
Retention of excess fluids
Risk factors: sitting or standing in one position for too long, low protein levels, obesity, and pregnancy.
Medication side effects
Venous insufficiency is a condition in which the veins in the legs are weakened or not working properly. As a result, the veins are not able to return blood to the heart efficiently, thus fluid ends up being forced out of the veins and into the surrounding tissue. This can lead to pooling of blood and fluid build up in the legs, resulting in peripheral edema.
Varicose veins, or enlarged and twisted veins, are a common risk factor for venous insufficiency.
Deep vein thrombosis occurs when a blood clot forms in a vein deep inside the body, usually affecting the legs. The blood clot can damage the vein and disrupt blood flow, leading to peripheral edema in the legs. Deep vein thrombosis can also cause venous insufficiency.
Congestive heart failure is when the heart cannot pump blood to the rest of the body as well as it should. As a result, blood may accumulate in the lower limbs and cause peripheral edema. In some cases, congestive heart failure may lead to fluid build up in the lungs as well, causing pulmonary edema, which may lead to shortness of breath. Congestive heart failure may also cause abdominal edema, also known as ascites.
Cirrhosis is a liver disease characterized by permanent scarring and fibrosis of the liver. When fibrosis becomes extensive, the liver can start to fail, and blood coming from the portal vein may start to back up, leading to portal hypertension (increased blood pressure in the portal vein). As a result, fluid may start to leak out of the portal vein and into the abdomen, leading to ascites. This fluid can also accumulate in the legs, resulting in peripheral edema. Over time, the high blood pressure in the portal vein can also cause varices, or enlarged veins, in the esophagus or abdomen.
Kidney disease can lead to the buildup of excess fluid and sodium in the body, which may cause fluid retention and lead to peripheral edema in the legs.
Damage to the nephrons (the small filtering units in the kidneys) can lead to nephrotic syndrome, which causes the kidneys to excrete too much protein in urine, resulting in declining protein levels in the blood and excess fluid retention.
How do you diagnose pitting edema?
In most cases, pitting edema can be diagnosed through clinical evaluation.
Medical history review
A grading system is often used to determine the severity of the edema on a scale from +1 to +4. It is assessed by applying pressure on the affected area and then measuring the depth of the pit (depression) and how long it lasts (rebound time).
Grade +1: up to 2mm of depression, rebounding immediately.
Grade +2: 3–4mm of depression, rebounding in 15 seconds or less.
Grade +3: 5–6mm of depression, rebounding in 60 seconds.
Grade +4: 8mm of depression, rebounding in 2–3 minutes.
Blood tests (varies depending on underlying cause)
How do you treat pitting edema?
Treatment is usually aimed at resolving the underlying cause and varies depending on the specific cause. Additional treatment to manage pitting edema depends on the severity.
Mild cases usually resolve on their own.
Elevation of the affected limb may help reduce swelling.
Severe cases may require prescription diuretic medications (e.g., furosemide).
Chronic cases will generally require long-term management of the underlying cause.
Compression socks may be recommended to promote circulation in the affected limb.
Frequently Asked Questions
Edema refers—more generally—to any swelling that arises from excess fluid build-up in the body. Edema occurs when something disrupts the fluid in the body, causing an accumulation of the interstitial fluid found in tissues. Pitting edema is a specific type of edema that is associated with pitting or indentation in the affected areas, and is often caused by conditions that lead to the pooling of blood in the feet or legs. The excess fluid that builds up in pitting edema is mainly composed of water. Conversely, non-pitting edema is typically associated with conditions affecting the thyroid or lymphatic system, and the resulting fluid build-up can be composed of a variety of substances, including proteins, salts, and water.
Is pitting edema serious?
Although pitting edema alone may not be serious, the underlying conditions causing it might be of more concern, so it is important to properly diagnose and treat them.
Over time, if pitting edema is left untreated, the swelling may cause long term tissue damage that results in stiff and cracking skin, as well as increased risk of infection in the affected tissues.
Watch related videos:
Related linksPulmonary edema
Congestive heart failure
Chronic kidney disease
Resources for research and reference
Mcgee, S. (2012). Evidence-Based Physical Diagnosis (3 edition). Philadelphia, PA: Elsevier Saunders.
Pomero, F., Re, R., Meschi, M., et al. (2017). Approach to leg edema. Italian Journal of Medicine, 11(3): 267. DOI: 10.4081/itjm.2017.771
Scallan, J., Huxley, V. H., & Korthuis, R. J. (2010). Capillary fluid exchange: Regulation, Functions, and Pathology. San Rafael, CA: Morgan & Claypool.
Yanagisawa, N., Koshiyama, M., Watanabe, Y., Sato, S., & Sakamoto, S. (2019). A Quantitative Method to Measure Skin Thickness in Leg Edema in Pregnant Women Using B-Scan Portable Ultrasonography: A Comparison Between Obese and Non-Obese Women. Medical Science Monitor, 25: 1–9. DOI: 10.12659/msm.911799