- Lymphatic filariasis is caused by parasitic worms leading to obstruction of lymphatic vessels.
- The most characteristic clinical manifestation is lymphedema, resulting from chronic lymphatic obstruction and subsequent swelling of the limbs.
- This chronic swelling can progress to elephantiasis due to fibroblast proliferation and tissue fibrosis.
- While hydrocele can occur, especially in males, it is considered a common but not the primary clinical hallmark.
- Petechiae and papilledema are unrelated to the pathophysiology of lymphatic filariasis.
- Therefore, lymphedema is the defining clinical feature reflecting the lymphatic damage caused by the infection.

Reference: Davidson’s Principles and Practice of Medicine, 24th Edition, Chapter: Tropical Medicine, Page 1061.