Uter, WolfgangWolfgangUterSchmidt, ErichErichSchmidtLessmann, HolgerHolgerLessmannSchnuch, AxelAxelSchnuch2018-11-072018-11-072012https://resolver.sub.uni-goettingen.de/purl?gro-2/26151Background. Evernia prunastri (oak moss) and Evernia furfuracea (tree moss) are lichens from which natural extracts are obtained. Objectives. To identify possible subgroups of E. furfuracea-sensitized patients according to whether these are allergic to lichen components or to contaminants. Methods. A retrospective analysis was performed of surveillance data collected by the Information Network of Departments of Dermatology () in 20032010 with oak moss absolute (1% pet.), tree moss absolute (1% pet.), and colophonium (colophony, 20% pet.). Results. In total, 3030 patients had been tested with all three allergens. Positive reactions to E. furfuracea were observed in 6.37%, to E. prunastri in 5.71%, and to colophonium in 4.82%. Concordance between positive reactions to E. prunastri and E. furfuracea was good only in patients not co-sensitized to colophonium (Cohen's ? = 0.681, 95% confidence interval 0.615-0.746). Moreover, E. furfuracea-sensitized patients showed (strong or extreme) concomitant reactions to colophonium significantly more often if not co-sensitized to E. prunastri. Conclusions. Two subgroups of E. furfuracea-sensitized patients are identifiable: (i) those with sensitization to (oxidized) resin acids, as indicated by positive patch test reactions also to colophonium, and (ii) those non-sensitized to resin acids, but sensitized to common constituents of E. prunastri and E. furfuracea.journal_article10.1111/j.1600-0536.2012.02064.x22486592000304993100006