Elephantiasis is a condition in which a part of the body becomes grossly enlarged due to a thickening of the skin and the underlying tissues. It results from a long-term interference with the flow of lymphatic fluid away from these tissues. The most frequently affected part of the body is the leg.
The most common cause of lymphatic obstruction is filariasis, an infection with parasitic roundworms known as filariae. Filariasis is caused chiefly by the species Wuchereria ban-crofti and Brugia malayi and is common in some tropical and subtropical parts of the world. Elephantiasis develops only after the infection has been present for many years. It is preceded by chronic swelling of the affected part and by acute attacks of inflammation within it. In men, the scrotum is affected about as frequently as the leg. Less often, elephantiasis occurs in the arm. Occasionally, the disease also affects the breasts or external genitals of women.
In a form of elephantiasis known as elephantiasis nostras, the lymphatic obstruction results from streptococcal infections of the subcutaneous tissues and the lymph vessels that drain them. Since the introduction of antibiotics, this form of elephantiasis has been disappearing.
In rare cases, elephantiasis may result from extensive surgical removal of lymph nodes or from a disease other than filariasis affecting the nodes.