Lymphedema may be classified as primary or secondary, based on underlying cause.

Primary Lymphedema results from abnormal development of the lymphatic system. Most cases are sporadic and have no family history, and are thought to occur secondary to an underlying developmental abnormality that manifests at some point later in life. Secondary Lymphedema describes Lymphedema that occurs through damage or dysfunction of normal lymphatics.

The most common causes of Lymphedema in developed countries are lymphatic damage from lymphadenectomy (lymph node dissection), radiation, infection, compression, trauma, burns, insect bites, vascular surgery or tumor invasion. Other causes include vein stripping, peripheral vascular surgery, lipectomy, burns and burn scar excision.

Worldwide, filariasis is the most common cause with damage to the lymphatics. Filariasis is caused by invasion by an offending parasite called Wuchereria bancrofti.