title: Contact allergy to essential oils cannot always be predicted from allergy to fragrance markers in the baseline series.
abstract: BACKGROUND
  Essential oils are fragrance substances that are labelled on cosmetic products by their INCI names, potentially confusing consumers.
  
  
  OBJECTIVE
  To establish whether contact allergy to essential oils might be missed if not specifically tested for.
  
  
  METHODS
  We tested 471 patients with 14 essential oils and 2104 patients with Melaleuca alternifolia oil between January 2008 and June 2014. All patients were tested with fragrance mix I, fragrance mix II, hydroxyisohexyl 3-cyclohexene carboxaldehyde, and Myroxylon pereirae. Three hundred and twenty-six patients were tested with hydroperoxides of limonene and linalool.
  
  
  RESULTS
  Thirty-four patients had a +/++/+++ reaction to at least one essential oil. Eleven had no reaction to any of the six marker fragrance substances. Thus, 4 of 11 positive reactions to M. alternifolia oil, 2 of 7 reactions to Cymbopogon flexuosus oil, 1 of 5 reactions to Cananga odorata oil, 3 of 4 reactions to Santalum album oil and 2 of 3 reactions to Mentha piperita oil would have been missed without individual testing.
  
  
  CONCLUSIONS
  A small number of patients who are allergic to essential oils could be missed if these are not specifically tested. Labelling by INCI names means that exposure may not be obvious. Careful inspection of so-called 'natural' products and targeted testing is recommended.
authors.affiliation: Department of Dermatology, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, S10 2JF, UK.
authors.forename: Ruth A
authors.initials: RA
authors.lastname: Sabroe
authors.affiliation: Department of Dermatology, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, S10 2JF, UK.
authors.forename: Catherine R
authors.initials: CR
authors.lastname: Holden
authors.affiliation: Department of Dermatology, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, S10 2JF, UK.
authors.forename: David J
authors.initials: DJ
authors.lastname: Gawkrodger
mesh_terms: D000080462:Acyclic Monoterpenes; D000447:Aldehydes / Q000009:adverse effects; D000485:Allergens / Q000009:adverse effects*; D054362:Cananga / Q000009:adverse effects; D003358:Cosmetics / Q000009:adverse effects / Q000737:chemistry; D053138:Cyclohexenes / Q000009:adverse effects; D031743:Cymbopogon / Q000009:adverse effects; D017449:Dermatitis, Allergic Contact / Q000209:etiology*; D006801:Humans; D000077222:Limonene; D036142:Mentha piperita; D039821:Monoterpenes / Q000009:adverse effects; D029904:Myroxylon / Q000009:adverse effects; D009822:Oils, Volatile / Q000009:adverse effects*; D010328:Patch Tests; D010476:Perfume / Q000009:adverse effects*; D010938:Plant Oils / Q000009:adverse effects; D011356:Product Labeling; D012189:Retrospective Studies; D032123:Santalum / Q000009:adverse effects; D020947:Tea Tree Oil / Q000009:adverse effects; D013729:Terpenes / Q000009:adverse effects
chemical_list: D000080462:Acyclic Monoterpenes; D000447:Aldehydes; D000485:Allergens; D003358:Cosmetics; D053138:Cyclohexenes; D039821:Monoterpenes; D009822:Oils, Volatile; D010476:Perfume; D010938:Plant Oils; D013729:Terpenes; D020947:Tea Tree Oil; D000077222:Limonene; C015424:peppermint oil; C018584:linalool; C092244:hydroxyisohexyl 3-cyclohexene carboxaldehyde
keywords: allergic contact dermatitis; cosmetic reactions; essential oils; fragrances