Contact dermatitis from Frullania, Compositae and other plants.

28 patients with dermatitis from plants were seen over the last 10 years. This was 1.45% of all patients with contact dermatitis. 7 reacted to Frullania, 4 to Compositae, and 1 to helenin. Patch tests with Frullanaceae, Lauraceae, Magnoliaceae, Compositae and helenin, showed no dominant allergen in the plant families with sesquiterpene lactone sensitivity. The positive reactions with feverfew (Chrysanthemum parthenium) in nearly all patients is probably due to the high content of the sesqueterpene lactone parthenolide; it is a better screening allergen for Compositae sensitivity than alantolactone (helenin).