The legs are preferentially affected by systemic edematous states. Pathogenetic factors are: increased hydrostatic pressure, increased capillary permeability (leak), reduced colloid-oncotic pressure, reduced lymph drainage and miscellaneous rare conditions. The most frequent cause of increased hydrostatic pressure is right heart failure, which can be treated with diuretic drugs. Increased capillary leak is seen in septic-toxic events, where the underlying disease must be treated. Reduced oncotic pressure is caused by hypoalbuminemia, either due to reduced production, e.g., in liver cirrhosis, or to increased albumin loss, e.g., through the kidney in nephrotic syndrome or the gut in protein-loosing enteropathy. Lymphedema is classified either as primary or secondary and is treated by lymph drainage. Idiopathic edemas, primarily seen in females, often lead to chronic abuse of diuretics, which in turn can cause diuretic-induced edemas.