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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

Edema (hydropsy) is an accumulation of fluid in the space outside of body cells, in a compartment called the interstitial space or tissue space. The fluid emerges from the vessels and accumulates in the tissue or in spaces within the body. The following preconditions are associated with the development of edemas:

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

Edema as an Accompanying Symptom

Edema may also accompany physical conditions not considered serious health issues. Edema may occur as part of the female cycle, or in people flying in airplanes—a natural occurrence due to the body being constrained in an unnatural position for a prolonged period of time.

Edema accompanying menstruation

Edema is a typical accompanying symptom in the field of gynecology and usually occurs in the second half of the cycle. It 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, this type of edema has not yet been fully studied. It generally affects 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, the legs and feet are mostly affected.

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

The female cycle impacts multiple processes

Blood vessels become more permeable in the second half of the menstrual 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 excess aldosterone in the second half of the cycle encourages the formation of edema.

Aldosterone is formed in the adrenal gland and generally helps regulate fluid balance. Increased release of serotonin may also contribute to the formation of edema. Serotonin influences the permeability of the vessels.

Edema during airplane flights

The causes of edema when flying are comparable to those of edema 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. As such, the blood gets caught in the veins and feet and legs swell.


The accumulation of fluid in the abdominal area is called ascites. Swollen abdomen is a typical symptom. Liver cirrhosis, infectious diseases, and cardiac disease are possible causes.

Ascites as part of a liver cirrhosis

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

Infectious diseases also have to be considered. 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

In pleural effusion, the amount of fluid in the pleura cavity exceeds a healthy limit. This condition can only be diagnosed if >200 ml of fluid has accumulated. Pleural effusion occurs frequently. In most cases, it is caused by cardiac insufficiency (bilateral), neoplasm (only on the 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 lung edema, the lung tissue, not the pleural cavity, is filled with fluid. Lung edema can be diagnosed quickly by means of lung ultrasound, an absolutely crucial exam. X-ray is also necessary. The mobile application of the sonography (ultrasound) is pertinent in this scenario.

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


Lymphedema comprises primary and secondary lymphedema. The primary form includes congenital familial lymphedema (Nonne-Milroy) and familial non-congenital lymphedema (Meige). The sporadic lymph edemas, which are caused by changes to the lymph vessels (hypoplasia or hyperplasia) also belong to the primary lymphedemas. Secondary lymphedemas can be:

  • Posttraumatic
  • Postoperative
  • Inflammatory
  • Neoplastic

Primary lymphedema usually occurs by age 35 and almost only affects women.

Characteristics of primary lymphedema

Primary lymphedema is characterized by the following symptoms:


It usually starts out in the toes, then spreads to the instep and 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 with pressure. The skin feels cool.

Other symptoms

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

Secondary lymphedema

Secondary lymphedema usually occurs after age 40. Men and women are affected equally. It usually develops on one side alone. This is not true when it is caused by an inflammatory process. Secondary lymphedemas can sometimes be attributed to parasites (filariasis). In that case, inflammatory changes to the lymph channels occur.

Treatment of lymphedemas

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

The manual removal of secondary lymphedema blockages as a result of malignant processes can activate metastases.


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 Anaphylactic Shock: Formation of Edema

Formation of edema as a similar disease pattern

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

Peripheral edemas occur e.g. in the ankles, but can also be found in the lower legs. 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 with pressure. Furthermore, consistency is significant, namely soft or hardened (indurated).

Quincke edema

Illustration of Angioedema

Image: Angioedema. By: BruceBlaus. License: CC BY 3.0

Quincke edema, also called angioneurotic edema, is acute and can last up to 3 days. It is a swelling that mostly affects the face (lips and eyelids), but the hands, feet, and genital area can also be markedly swollen. Quincke edema becomes lethal when upper respiratory tract swelling occurs.

Differential diagnosis of Quincke edema

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

Reinke edema

Image of a Reinke edema

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

Reinke edema is a disease affecting the vocal folds. Tissue fluid is embedded on one or both sides, and the entire vocal chord may be affected. The patient notices the 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 reduce the swelling. The patient is advised to avoid chemical vapors and other harmful influences such as smoking. The above-mentioned are often the cause of the Reinke edema in the first place. In severe cases, surgery can become necessary.

Perifocal edema

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

Pretibial edema

Pretibial edema refers to an accumulation of fluid in the subcutaneous tissue of the shinbone (tibia). Its occurrence usually indicates an obstruction of lymph flow. This condition is easily diagnosed but can have different causes.

Possible causes of 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 pretibial edema can occasionally point to very serious underlying causes.

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