Airborne contact dermatitis from Compsoitae oleoresins simulating photodermatitis.

American ragweed (Ambrosia) dermatitis has an airborne pattern and is caused by lipid soluble oleoresins of pollens. A similar weed dermatitis has been described in India and Australia. The weeds involved were all of the Compositae family and contain sesquiterpene lactones with one common antigenic determinant. This study reports seven Danish patients treated for many years under the diagnosis of photodermatitis, who eventually proved to suffer from Compsoitae oleoresin dermatitis. Probably, Compsitae dermatitis is a world-wide disease, although aften misdiagnosed as has happened in Scandinavia.