The pathogenesis of Henoch Schonlein purpura (HSP) is unknown but is b
elieved to result from an immune complex reaction to various antigenic
stimuli, such as infectious agents. However, its association with Ent
amoeba histolytica has not been reported before. We present an Ii-year
-old boy with HSP, confirmed by the demonstration of leukocytoclastic
vasculitis from skin and diffuse endocapillary proliferative glomerulo
nephritis, together with immunoglobulin A and complement component C3
deposition from renal biopsies. Cysts and trophozoites of Entamoeba hi
stolytica were detected from the stool of the patient at the same time
and disappeared after the treatment with metranidasole. The temporal
association of these two disorders is either coincidental or due to a
causal relationship between them.