Fever and urticaria in acute giardiasis.

Travelers' diarrhea afflicts some 250 million people yearly. A number of etiologic agents have been identified, including bacteria, viruses, and parasites. Giardia lamblia is one of the pathogens clearly associated with this syndrome. Typical symptoms of giardiasis that include abdominal bloating and cramps are well known, whereas urticaria has rarely been associated with this illness. An American tourist developed acute giardiasis accompanied by urticaria and high fever. No other pathogens were identified, and response to metronidazole therapy was prompt. Giardiasis should be included in the differential diagnosis of acute urticaria and fever in the traveler.