Allergic contact dermatitis in food handlers, with patch tests positive to Compositae mix but negative to sesquiterpene lactone mix

Several studies have pointed out that the sesquiterpene lactone (SL) mix is a safe, though inadequate, screen for Compositae allergy. To test the usefulness of the sesquiterpene lactone parthenolide as a supplementary Compositae screening test to the mix, both were included in the standard series in 2 Danish dermatology departments. Among 2244 patients tested, 46 (2%) were positive to SL mix and 73–75% of these were positive to parthenolide. The results demonstrate that parthenolide is not suitable as a supplementary screening agent to SL mix, but may be a fairly good screen on its own if the mix is not available.