Anaphylactic reaction after the ingestion of chamomile tea: a study of cross-reactivity with other composite pollens.

We report a case of an 8-year-old atopic boy in whom ingestion of a chamomile-tea infusion precipitated a severe anaphylactic reaction. The patient suffers from hay fever and bronchial asthma caused by a variety of pollens (grass, olive, and mugwort). This severe reaction was developed after his first ingestion of chamomile tea. Studies revealed the presence of immediate skin test reactivity and a positive passive transfer test to chamomile-tea extract. Moreover, both specific antichamomile-tea extract and anti-Matricaria chamomilla-pollen extract IgE antibodies were detected by an ELISA technique. Cross-reactivity among chamomile-tea extract and the pollens of Matricaria chamomilla, Ambrosia trifida (giant ragweed), and Artemisia vulgaris (mugwort), was demonstrated by an ELISA-inhibition study. These findings suggest a type I IgE-mediated immunologic mechanism as being responsible for the patient's anaphylactic symptoms and also suggest that the patient cross-reacted the pollens of Matricaria chamomilla contained in the chamomile tea because he was previously sensitized to Artemisia pollen.