This document discusses the differences between edema and lymphedema. Edema results from an imbalance in fluid pressures across capillary membranes that causes excess fluid accumulation in tissues. It is a normal response to injury and the fluid decreases as healing occurs. Lymphedema is a persistent and excessive accumulation of fluid and proteins in tissues caused by impairment of the lymphatic system. It leaves marks when pressed into the skin and is not relieved by diuretics like edema sometimes is. Factors that can contribute to lymphedema include congenital malformations, infections, obstructions, fibrosis, trauma, surgery, radiation therapy, and surgical dissection of lymph nodes.