Airborne contact dermatitis from Compositae plants in northern India

60 patients (45 male and 15 female) with suspected airborne contact dermatitis from Compositae (Asteraceae) plants and 20 age-matched controls (15 male and 5 female) were investigated. Patch tests were performed with ethanolic plant extracts of 4 Compositae plants, Parthenium hysterophorus, Chrysanthemum morifolium, Dahlia pinnata and Tagetes indica, all prevalent in northern India. 55 (92%) patients showed positive patch tests, with 35 (64%) demonstrating positive tests to extracts of only 1 of the 4 plants tested. No positive patch tests were seen in the controls. Parthenium hysterophorus (78%) was the most frequent plant reacting, followed by Chrysanthemum morifolium (42%), Dahlia pinnata (18%) and Tagetes indica (7%).