Swollen Legs: Main Causes of Edema and What They May Mean

Edema is the excessive accumulation of fluid in organs and extracellular tissue spaces. It is most noticeable in the legs: the feet and lower legs are the first to bear the hydrostatic load. Below is a breakdown of the causes, signs, and the boundaries beyond which a doctor is needed.

What leg edema is and how it manifests

Edema, or oedema, is an excess of fluid in the tissues. Most often it appears in the area of the feet, ankles, and lower legs, although it can also affect the whole body. By mechanism, edema can be hydrostatic, hypoproteinemic, or membranogenic.

Manifestations: swollen feet, ankles, or lower legs — on one or both sides; the skin is shiny and taut; its color changes, dryness, discomfort, and stiffness appear; pressure leaves a pit. Edema can be local or general. Pronounced general edema is usually preceded by hidden fluid accumulation of up to 4–9 L — pre-edema.

Why legs swell: heart, veins, kidneys, and other causes

Causes differ by level — from everyday to cardiac. Common ones include: prolonged standing or sitting in one position, excess salt in food, excess body weight, pregnancy, certain medications (some blood pressure medications, contraceptives, hormone therapy, antidepressants, steroids), varicose veins, and thyroid problems.

• Heart: edema in heart disease is the most common cause of hydrostatic edema and the most important indicator of heart failure; first the feet and lower legs when upright, the sacrum and lower back when horizontal, later total edema of the subcutaneous tissue and fluid in body cavities are possible.
• Veins and lymph: in thrombophlebitis the edema is firm, the skin over the thrombus is often inflamed and purplish, and palpation is painful; when lymphatic outflow is impaired, the edema of the limb is firm and the skin is pale.
• Kidneys and liver: renal edema appears on the whole body and face, especially around the eyes, it is soft, and the skin over it is pale; in liver cirrhosis, edema is usually combined with ascites and is located on the legs, lower back, and anterior abdominal wall.
• Local causes: trauma, such as a sprain, an insect bite, infection, inflammatory edema with reddish and painful skin, a thrombus.
• Other: sunburn, prolonged walking in hot weather, problems with lymph nodes, especially after mastectomy.

Why legs swell at the bottom and in women

When the body is upright, edema in heart disease initially occurs on the feet and lower legs.

In women, causes of edema include pregnancy, use of contraceptives, and hormone therapy. Edema can be local or general, that is, affect the whole body.

Which signs indicate a dangerous cause of edema

Unilateral edema without a clear cause, edema after trauma that worsens, as well as severe painful edema are reasons for an urgent consultation. Edema of the face or abdomen, redness and heat of the skin in the edematous area, high temperature, chills, and in a person with diabetes — edema of the feet, ankles, or lower legs are concerning.

Leg edema by itself is not a reason to call an ambulance. Call 103 or 112 if shortness of breath or difficulty breathing, pressure, heaviness, or chest pain, hemoptysis, noticeable palpitations, as well as dizziness, fainting, confusion, nausea, or cold sweat appear.

What examinations are prescribed for edema

Diagnosis begins with examination and palpation: after pressure on the edematous area a pit remains, tissue density, skin color and temperature, and symmetry of the edema are assessed. The doctor clarifies whether there is already a diagnosed disease of the heart, kidneys, or leg veins, what medications the person takes, and whether there was trauma.

The further set of examinations depends on the cause found and is determined by the doctor. Treatment of edema that does not resolve on its own is also built around the cause, not around the symptom itself.

When leg edema requires seeing a doctor

See a doctor routinely: if both feet, ankles, or lower legs are swollen and the edema does not resolve within several days, if the edema is worsening, if there is already a diagnosis affecting the heart, kidneys, or leg veins.

Without waiting — for any alarming sign from the list above.

Reference material describes the picture rather than making a diagnosis: the final explanation for your case is given by a doctor at a consultation.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer