In Reply.—Dr Rosario's comments concerning the role of parasites as a cause of urticaria in Brazil support the impression that children with chronic urticaria should be examined for parasites. His mention of a child with an exacerbation of urticaria after antihelminthic chemotherapy is interesting. Although our report1 and the report of Cohen and Criep2 observed this phenomenon with protozoan infections, to my knowledge Dr Rosario is the first to note it in helminthic infections. I agree with Dr Rosario that when treating parasitic infections in children with urticaria, physicians should be prepared for the possibility of causing an intense urticarial response. As he suggests, treatment with epinephrine should be effective, so that treatment of the underlying parasitic infection need not be delayed. I also agree that the sudden release of parasite antigen is the most likely explanation for this response. A better understanding of these events will