Oxidized citrus oil (R-limonene): a frequent skin sensitizer in Europe

J Am Acad Dermatol. 2002 Nov;47(5):709-14. doi: 10.1067/mjd.2002.124817.


Background: Peel oil from citrus fruits consists of R-(+)-limonene, which is one of the most commonly used fragrance materials in technical products and in fine fragrances. This substance forms allergenic oxidation products during handling and storage.

Objective: We wanted to study the frequency of allergic reactions to oxidized R-(+)-limonene in patients with dermatitis and find a suitable test preparation.

Method: Patch testing with oxidized R-(+)-limonene was performed on 2273 patients at 4 dermatology clinics in Europe.

Results: Of the consecutive patients tested, 3.8% to 3.9% had positive reactions in two of the clinics; 6.5% had positive reactions in the third clinic; and 0.3% had positive reactions in the fourth clinic. A total of 63 patients showed positive reactions. In total, 57% of the patients did not react to fragrance mix or balsam of Peru. We recommend testing with 3% oxidized R-(+)-limonene in patients referred for patch testing.

Conclusion: The high frequency of oxidized limonene allergy provides clinical evidence for the European classification of R-(+)-limonene that contains oxidation products as skin sensitizers.

MeSH terms

  • Cosmetics
  • Cyclohexenes
  • Europe
  • Female
  • Humans
  • Hypersensitivity / etiology*
  • Limonene
  • Male
  • Patch Tests
  • Terpenes / immunology*


  • Cosmetics
  • Cyclohexenes
  • Terpenes
  • Limonene