The sensitizing capacity of Compositae plants. III. Test results and cross-reactions in Compositae-sensitive patients.

25 patients known or suspected to be allergic to different Compositae plants were tested epicutaneously with ether extracts of different Compositae species. 14 persons revealed a chrysanthemum hypersensitivity, 2 were allergic to arnica and 2 to camomile. In 1 patient a positive reaction to tansy was obtained. In the case of the chrysanthemum allergy, this was induced occupationally. All other patients had sensitized themselves by non-occupational contact. Cross-reactions were seen to tansy [14], yarrow [11], camomile [10], arnica and sunflower [5]. The components which are responsible for the sensitization as well as for the crossreactions are sesquiterpene lactones.