Skip to Content


Pronunciation: lo-i'a-sis

Definition: A chronic disease caused by the filarial nematode Loa loa, with symptoms and signs first occurring approximately 3–4 years after a bite by an infected tabanid fly. When the infective larvae mature, the adult worms move about in an irregular course through the connective tissue of the body (as rapidly as 1 cm/minute), frequently becoming visible beneath the skin and mucous membranes; in the back, scalp, chest, inner surface of the lip, and especially on the conjunctiva. The worms provoke hyperemia and exudation of fluid, often a host response to the worm products, a Calabar or fugitive swelling that causes no serious damage and subsides as the parasites move on; the patient is annoyed by the “creeping” in the tissues and intense itching, as well as occasional pain, especially when the swelling is in the region of tendons and joints. Many patients have marked eosinophilia (10–40%).

Synonym(s): Calabar swelling, fugitive swelling

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

© Copyright 2018 Wolters Kluwer. All Rights Reserved. Review date: Sep 19, 2016.