Pitting Edema

What Is It, Causes, Grading, Diagnosis, Treatment, and More

Author: Ahaana Singh

Editors: Antonella Melani, MD, Lisa Miklush, PhD, RN, CNS

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.

What is the difference between edema and pitting edema?

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.

What causes pitting edema?

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. 

Pitting edema can have several different causes. It may be the result of localized problems with blood vessels, a side effect of certain medications, or a sign of other underlying conditions. 

Common factors

Pitting edema is commonly caused by poor circulation or the retention of excess fluids. Some common risk factors that may lead to these problems include sitting or standing in one position for too long, low protein levels, obesity, and pregnancy. 

Medications 

Certain medications may increase the risk of pitting edema, such as high blood pressure medication, non-steroidal antiinflammatory drugs (NSAIDs), steroids, estrogens, and certain diabetes medications. 

Venous insufficiency

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

Deep vein thrombosis occurs when a blood clot forms in a vein deep inside the body, usually 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

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

Cirrhosis is a liver disease characterized by permanent scarring and fibrosis of the liver, which receives blood from the spleen and gastrointestinal organs via the portal vein. 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, which refers to 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

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. This can also give rise to peripheral edema.

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.

How do you diagnose pitting edema?

When diagnosing pitting edema, a physical examination and review of medical history may be enough to determine the underlying cause. In some cases however, additional diagnostic testing, such as blood tests, X-rays, and ultrasound exams may be necessary to assess a potential underlying cause. 

How do you grade pitting edema?

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.

How do you treat pitting edema?

To treat pitting edema, it is important to diagnose and treat its underlying cause. Additional treatment for pitting edema will depend on its severity. Most cases of mild pitting edema will resolve on its own, but can be facilitated by elevating the affected limb. In more severe cases—or if the pitting edema is caused by critical conditions, such as congestive heart failure, liver disease, or kidney damage—a diuretic medication may be prescribed to help eliminate the excess fluid through urine. In chronic cases, compression socks can be used to promote circulation in the affected limb. 

What are the most important facts to know about pitting edema?

Pitting edema occurs when excess fluid in the body causes swelling that indents when pressure is applied. It usually occurs in the lower limbs of the body, and may result from localized problems with blood vessels, side effects of certain medications, or existing underlying conditions that cause disrupted blood flow or excess fluid retention. To treat pitting edema, it is important to diagnose and treat its underlying cause. Additional treatment for pitting edema will depend on its severity. Mild pitting edema may resolve temporarily with limb elevation. For more severe cases, however, a diuretic medication may be prescribed. In chronic cases, compression socks can be used. 

Related links

Pulmonary edema
Congestive heart failure
Chronic kidney disease
Cirrhosis

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