| Primary venous reflux, superficial or deep |
Right-side heart, renal or hepatic failure |
| Postthrombotic syndrome (deep vein obstruction and reflux) |
Medications |
| Lymphedema, primary and secondary |
Central venous obstruction (postthrombotic, congenital or mass) |
| Nonthrombotic iliac vein obstruction (including mass compressing an iliac vein) |
Hypoalbuminemia or proteinemia |
| Calf muscle pump impairment (musculoskeletal or neurological) |
Lymphedema |
| Vascular malformations |
Obesity |
| Overgrowth syndromes |
Medications |
| Complex regional pain syndrome (reflux sympathetic dystrophy) |
Lipedema |
| Mass, soft tissue, or bone |
Immobility |
