Pitting vs Non Pitting Edema

Any form of pressure can indicate pitting edema, including elastic in socks or tight clothing. Doctors identify pitting edema by applying pressure to the swollen area - simply depressing the skin with a finger. If this causes an indentation that stays for some time after the release of the pressure, this type of edema is referred to as pitting edema.

The indentation made on the skin is due to the fluid leaking out of the capillaries into the subcutaneous tissue. The extent and duration of the indentation are good indications of the severity of the pitting edema.

Assessment of Pitting Edema

Understanding Pitting Edema

Conditions involving the heart, liver, and kidneys are critical causes of pitting edema.

Patients who receive intravenous fluids can also develop edema. Systemic diseases like rheumatoid arthritis often cause pitting edema, as they affect the various organ systems of the body. An isolated condition that involves an extremity (like a twisted ankle) can also cause pitting edema.

Diagnosing Non-Pitting Edema

With this type of edema, pressure on the affected area does not persist. This type of edema is more complex than pitting edema, as the process involves more than fluids simply filling up interstitial spaces. Doctors believe that the fluid is less sensitive to touch due to some internal pressure affecting the swollen area - that it’s “pushing back”.

Understanding Non-Pitting Edema

Non-pitting edema is often associated with three medical conditions - myxedema, lipedema, and lymphedema.

In myxedema (a condition involving underactive thyroid gland), the tissues are gradually filled with water-loving hyaluronan molecules which attract fluid to the tissues. These molecules absorb water and swell up to cause the edema. This creates pressure (osmotic pressure) that acts against the external pressure caused by touch. The osmotic pressure would make the affected area appear taut.

Non-pitting edema of the legs is known as pretibial myxedema, which involves swelling of the skin that occurs in patients with hyperthyroidism.

A similar mechanism is involved in lipedema and lymphedema, conditions in which the lymphatic system breaks down and the lymph nodes swell up. Lymphedema may be a congenital disorder (present at birth) or can occur after mastectomy or lymph node surgery. The osmotic pressure generated by the swollen lymph nodes may be responsible for the constant internal pressure pushing the fluids against the skin. This occurs even when pressure is applied to the affected area.

Non-pitting edema usually affects the legs or arms. If the pressure applied to the skin does not result in a persistent indentation, this type of edema is referred to as non-pitting edema.

Pitting and Non-Pitting Edema Are Treatable

Sometimes pitting edema and non-pitting edema occur without any underlying disease and this is known as idiopathic edema. This is common in women who experience it in legs and feet, during their pre-menstrual or pre-menopausal period.

You don't have to live with edema of any kind forever. Treatment of edema depends on the causes of edema and whether it is temporary or permanent.

To treat either type of edema, doctors will first determine the cause and whether it is temporary or permanent. Initial treatment will focus on that medical condition.