Is all swelling lymphedema?
No. There are two main categories of lymphedema: Primary & Secondary. In these conditions, a defining characteristic is an accumulation of protein-rich fluid. There is a third category of swelling that is edema & typically there is an underlying medical issue in this case. To further explain:
Primary Lymphedema is an abnormal development of the lymphatic structures leading to poor lymphatic drainage. This abnormal development includes any of these forms: Aplasia (lymphatic channels haven’t been developed or are absent); Hypoplasia (underdeveloped lymphatic structures with lymph nodes being less in number &/or size); Hyperplasia (too many lymphatic structures with abnormal valves contributing to reflux). Primary lymphedema is a congenital defect that can appear at birth or later in life.
Secondary Lymphedema is more common & a condition that is acquired due to trauma to the lymphatic system (such as from surgery, cancer treatment, infections, lymph node removal, Cellulitis, etc.). In the United States, breast cancer is the leading cause of secondary lymphedema. World-wide, the leading cause is Filariasis.
Additional related conditions that can lead to an abnormal lymphatic state include Lipedema, Obesity, Chronic Venous Insufficiency, Chronic Regional Pain Syndrome, Dependent positioning & Immobility (such as after a stroke or spinal cord injury), Congestive Heart Failure, Malnutrition & Kidney Disorders among other conditions.