Contact allergy to Compositae plants in patients with atopic dermatitis.

To investigate the frequency of Compositae sensitivity is one of the most important goals of current dermatology and allergology. We have patch tested 30 adult patients suffering from "extrinsic" atopic dermatitis with sesquiterpene lactone mix and Compositae mix including Compositae mix individual ingredients, extracts of arnica (Arnica montana), chamomile (Chamomilla recutita), tansy (Tanacetum vulgare), fever few (Tanacetum parthenium) and yarrow (Achillea millefolium) as well as with specific series for patients with atopic dermatitis. All allergens were purchased from Hermal-Trolab (Reinbek, Germany). There were 6 (20%) patients positive to Compositae mix only, and 3 (10%) patients positive to both Compositae mix and sesquiterpene lactone mix. Among 9 Compositae mix-sensitive patients 8 (88.8%) were positive to at least 1 of its individual ingredients: 5 (55.5%) to chamomile, 4 (44.4%) to arnica, 2 (22.2%) to tansy, and 2 (22.2%) to fever few. Among Compositae-sensitive patients 78.8% had other contact allergies, most often to nickel (33.3%). Since our study represents the first report on contact allergy to Compositae among patients with "extrinsic" type of atopic dermatitis, it substantiates the statement that atopy represents a risk factor for Compositae allergy. In conclusion, the overall prevalence of 30% Compositae-sensitive among patients with "extrinsic" atopic dermatitis detected in our study represents a basal sesquiterpene lactone mix detection rate of 10%, reinforced and safely supplemented by 20% by testing with the Compositae mix.