Results of aimed patch testing with constituents of sesquiterpene lactone (
SL) mix, Compositae mix (CM) and other Compositae extracts and allergens in
190 Compositae-allergic patients detected in an 8-year period are presente
d. Feverfew of CM elicited positive reactions most frequently, followed by
tansy, wild chamomile, yarrow and arnica, whereas dehydrocostus lactone of
SL was the most frequent elicitor of positive reactions, followed by alanto
lactone and costunolide. Chrysanthemum (Dendranthema) and marguerite (Argyr
anthemum frutescens) were the most important suspected sensitizers in both
occupationally and nonoccupationally exposed, and cross-reactions between c
hrysanthemum and feverfew/tansy/chamomile may partly explain the high preva
lence of positive reactions to the 3 last mentioned. In the nonoccupational
ly sensitized group, garden plants such as feverfew, blanket flower (Gailla
rdia), elecampane (Inula helenium), large yellow ox-eye (Telekia speciosa)
and cosmea (Cosmos) were additional important allergenic plants. The 3 last
mentioned were picked up by SL mix. Most of the lettuce-sensitized persons
were CM-positive. 19% of the occupationally sensitized group were negative
to both SL and CM, making very aimed patch testing necessary, notably when
suspecting rare sensitizers such as Gerbera and star of the veldt (Osteosp
ermum). The significance of the weeds dandelion, dog fennel and ox-eye dais
y as sensitizers is not clarified, but they are probably less important tha
n cultivated plants. (C) Munksgaard, 2001.