Lymphedema occurs when lymph fluid builds up in tissues because the lymphatic system is unable to drain it normally. Swelling may affect an arm, leg, or another area and can be accompanied by heaviness, tightness, skin changes, or reduced movement. This article discusses possible causes, risk factors, symptoms, stages, diagnostic assessment, compression methods, skin care, treatment approaches, and long-term management. General educational information about lymphedema is provided by Rivea Vascular Institute.