Edemas frequently accompany different illnesses. Distinguishing between the different types allows doctors to draw conclusions about the disease triggering the edema. Some edemas accompany symptoms of life-threatening processes. Comprehensive knowledge of edemas is therefore crucial.
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Pitting edema during and after the application of pressure to the skin.

Image: “Pitting edema during and after the application of pressure to the skin.” by James Heilman, MD. License: CC BY-SA 3.0

Definition: What Are Edemas?

Edema of the skin caused by inflammation

Image: “Edema of the skin caused by inflammation” by Klaus D.Peter. License: CC BY 3.0 DE

An edema (hydropsy) is defined as an accumulation of water in the space outside of body cells, in a compartment called interstitial space or tissue space. The water emerges from the vessels and accumulates in the tissue or in spaces within the body. The following preconditions can be tied to the development of edemas:

  • Protein deficiency (colloid osmotic or oncotic pressure sinks) due to nephropathies or hepatopathies.
  • Cell walls are permeable (due to inflammations, sepsis or allergies)
  • Obstruction to lymph flow
  • Increased hydrostatic pressure

Edemas as Accompanying Symptoms

Edemas may also accompany physical conditions not considered serious health issues. They may occur as part oft the female cycle, or in people flying in airplanes, as the normal result of the body being constrained in an unnatural position for a prolonged period of time.

Edemas accompanying menstruation

Edemas are a typical accompanying symptom in the field of gynecology. They usually occur in the second half of the cycle. They may not be visible, but can cause unpleasant or painful feelings of tension. The enclosed fluid also leads to weight gain. This is referred to as Cyclic Premenstrual Edema or Cyclical Idiopathic Edema. As the name implies, these edemas have not yet been fully studied. They generally affect the legs, feet, hands and/or chest. The symptoms always occur on both sides and simultaneously. In the first part of the day, the upper part of the body is usually affected, and in the second part it is mostly the legs and feet.

Note: Hormone-related edemas always occur on both sides of the body and simultaneously.

The female cycle impacts multiple processes

Presumably, blood vessels become more permeable in the second half of the cycle. Fluid and proteins get into the tissue. This process is more pronounced in some women than in others and is triggered by a hormonal imbalance. Science suggests that the release of too much aldosterone in the second half of the cycle encourages the formation of edemas.

Aldosterone is formed in the adrenal gland and generally helps regulate the fluid balance. An increased release of serotonin may help the formation of edemas, too. Serotonin influences the permeability of the vessels.

Edemas when flying

The causes for the formation of edemas when flying are comparable to those of edemas stemming from a unilateral physical strain, such as standing for a long time on the job. The muscular pump cannot work properly during physical inactivity, the blood gets caught in the veins, and feet and legs swell.


The accumulation of fluid in the abdominal area is called ascites. A swollen abdomen is a typical symptom. Liver cirrhosis, infectious diseases or cardiac disease count among the possible causes.

Ascites as part of a liver cirrhosis

Ascites occur frequently in the course of an advanced liver cirrhosis with portal hypertension. Simultaneously, obstructions of the protein biosynthesis and changes in the water electrolyte balance occur. However, as part of a differential diagnosis, tumor diseases should be considered. Diagnosis of ascites includes a procedure called paracentesis (removing liquid ascitic for its analysis) and some cases a liver biopsy is necessary.

Infectious diseases have to be considered in the process as well. Typical therapy includes the treatment of the principal cause of ascites (for example diuretics and antibiotics) and diet adjustments depending on the cause.

Pleural Effusion

When the amount of fluid in the pleura cavity exceeds a healthy limit, we speak of pleural weeping. This condition can only be diagnosed once more than 200 ml has accumulated. Pleural effusion happens frequently. In most cases, it is caused by cardiac insufficiency (bilateral), neoplastic (only in left side), hypoalbuminemia, and inflammatory infections in the lung. As part of the differential diagnosis, systemic diseases have to be considered as well as metabolic and abdominal diseases. In less severe cases of pleural effusion, the patient is not usually aware of the condition. In severe cases, the patient may complain of:

  • Dyspnea
  • Chest tightness
  • Chest pain when breathing (pleuritic pain)
  • Cough

Distinction from lung edema: In that case, the lung tissue fills with water. It can be diagnosed quickly by means of a lung ultrasound, an absolutely crucial exam. X-ray is also necessary. The mobile application of the sonography (ultrasound) is hence of the utmost urgency.

Note: A sonography has to be performed immediately if dyspnea and chest tightness occur.

Lymph Edema

We differentiate between primary and secondary lymph edemas. The primary edemas include the congenital familial lymph edema (Nonne-Milroy), and the familial non-congenital lymph edema (Meige). The sporadic lymph edemas, which are caused by changes to the lymph vessels (hypoplasia or hyperplasia) also belong to the primary lymph edemas. Secondary lymph edemas can be:

  • Posttraumatic
  • Postoperative
  • Inflammatory
  • Neoplastic

The primary lymph edema usually occurs by age 35 and almost only affects women.

Characteristics of the primary lymph edema

The primary lymph edema is characterized by the following symptoms:


It usually starts out in the toes, then spreads to the instep and the ankles. Both legs are usually swollen.

Shape and consistency of the edema

The instep seems swollen. Eventually, a columnar deformation of the lower leg occurs. The skin is not discolored, but may look pale. From an early stage, the edema feels hard and can barely be dented. The skin feels cool.

Other symptoms

The affected body parts hurt. Patients complain about a feeling of heaviness.

The secondary lymph edema

The secondary lymph edema usually occurs after age 40. Men and women are affected equally. It usually only develops on one side. This is not true when it is caused by an inflammatory process. Secondary lymph edemas can sometimes be attributed to parasites (filariosis). In that case, inflammatory changes to the lymph channels happen.

Treatment of lymph edemas

The type of therapy depends on the cause of the edema. There is a wide range of conservative treatments. A surgical procedure is usually only necessary when edemas lead to a certain disability. Physical measures such as specialized pressure boots, gymnastics and manual therapies are suited to dissolve blockages. The goal is to allow the patient to manage his day-to-day routine and continue his work as far as possible.

The manual removal of secondary lymph edema blockages as a result of malign processes can activate metastases.

The Lipedema

The lipedema is not an accumulation of fluid, but fatty tissue. Lipedemas are painful and typically occur symmetrically on the hips, thighs and upper arms. They may also be accompanied by peripheral edemas. The term lipedema is derived from Greek and means ‘fat swelling’.

Differential Diagnosis of the Anaphylactic Shock: Formation of Edemas

Formation of edemas as a similar disease pattern

Edemas can occur during anaphylactic shock, but they may be triggered by something different altogether. Edemas are distinguished by their localization. They are referred to as generalized (symmetric) or localized (one side or both sides). They can also occur on the periphery.

Peripheral edemas occur e.g. in the ankles, but can be found in the lower legs too. In bedridden patients, sacral edemas may occur. Another distinction is made according to palpation, depending on whether the edema can be dented or not dented. Furthermore, the consistency is significant, namely soft or hardened (indurated).


Illustration of Angioedema

Image: “Angioedema.“ by BruceBlaus. License: CC BY 3.0

The Quincke-edema, also called angioneurotic edema, is acute and can last up to three days. It is a swelling that mostly affects the face (lips and eyelids), but also the hands, feet and genital area can swell up extremely. The Quincke-edema turns lethal when the upper respiratory tract swells.

Differential diagnosis Quincke-edema

The Quincke-edema can be genetically determined and is caused by a lack of enzymes, in which case it is referred to as a hereditary angioedema. This is, however, very rare. This edema can also be caused by a physical stimulation, or it can accompany chronic infections or autoimmune diseases. Finally, there is an idiopathic type, where the cause is unclear.


Image of a Reinke edema

Image: “Reinke Ödem.“ by Welleschik. License: CC BY-SA 3.0

The Reinke-edema is a disease affecting the vocal folds. Tissue fluid is embedded on one or both sides, and the complete vocal chord may be affected. The patient notices his voice getting deeper or even breaking. Talking for a long time becomes challenging, and the patient may experience hoarseness.


Treatment of Reinke-edema

Sprays containing cortisone are used to make the swelling go down. The patient is supposed to avoid chemical vapors and other harmful influences such as smoking. Those are oftentimes what caused the Reinke-edema in the first place. In severe cases, surgery can become necessary.

Perifocal edema

A perifocal edema is located in the healthy tissue surrounding the seat of a disease. It can occur with e.g. abscesses, but also tumors and hemorrhages. This edema may also be a complication following radiotherapy.

Pretibial edema

The pretibial edema refers to an accumulation of fluid in the subcutaneous tissue of the shinbone (tibia). Its occurrence usually indicates an obstruction of the lymph flow. These edemas are easily diagnosed, but can have different causes.

Possible causes of the pretibial edema

Right ventricular insufficiency is considered the most common cause (cardiac edema). Other causes include chronic venous insufficiency or endocrine diseases (myxedema), or causes may also lie within the lymph system. Diagnosing the edema is absolutely crucial, since the pretibial edema can point to sometimes very serious underlying causes.

Popular Exam Questions on Edemas

The answers are below the references.

1. Water retention during the female cycle can be caused by:

  1. Shortage of aldosterone
  2. Shortage of serotonine
  3. It is just imaginary
  4. Cyclic premenstrual edema or cyclic idiopathic edema
  5. Increase in estrogen

2. Hormone-related edemas…

  1. …always occur on both sides.
  2. …sometimes occur on both sides.
  3. …never occur on both sides simultaneously.
  4. …are invisible.
  5. …only form on the legs.

3. The primary lymph edema…

  1. …is soft.
  2. …can be columnar.
  3. …is accompanied by the generation of warmth.
  4. …is accompanied by skin discoloration.
  5. …becomes hardened in its course.

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