Contact sensitization to calocephalin, a sesquiterpene lactone of the guaianolide type from cushion bush (Leucophyta brownii, Compositae)

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BackgroundCushion bush [Leucophyta brownii Cass.=Calocephalus brownii (Cass.) F. Muell.] is an Australian Compositae shrub that has been introduced into Scandinavia as a pot plant. The first case of sensitization occurred in a gardener, and the main allergen was identified as the guaianolide calocephalin. ObjectiveTo present the identification of the main allergen, and to assess the prevalence of sensitization to calocephalin in Compositae-allergic patients. Materials and methodsCalocephalin was isolated from a dichloromethane extract of aerial parts of cushion bush. Calocephalin 0.1% ethanol was included in the plant series in Malmo, Sweden, and Odense, Denmark. ResultsNuclear magnetic resonance (NMR) analysis of calocephalin resulted in a revision of its chemical structure to 4-acetoxy-1,2-epoxy-5,10H-guai-11(13)-en-12,8-olide. The prevalence of patch test positivity was up to 28% in aimed patch testing. Despite strongly positive patch test reactions, the relevance was unknown in the majority of cases, and only 1 person was occupationally sensitized. ConclusionCalocephalin is a potent contact allergen, but, as cushion bush is a low-maintenance pot plant, primary sensitization is most likely to occur through occupational exposure. Positive reactions in Compositae-sensitive persons probably occur because of cross-reactivity, and patients should be warned about contact with cushion bush plants.


  • Evy Paulsen
  • Lars P. Christensen
  • Monica Hindsén
  • Klaus E. Andersen
Enheter & grupper

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Dermatologi och venereologi


Sidor (från-till)303-310
TidskriftContact Dermatitis
Utgåva nummer5
StatusPublished - 2013
Peer review utfördJa