Allergy to oxidized limonene and linalool is frequent in the U.K

• Published in: British journal of dermatology (1951) Vol. 171; no. 2; pp. 292 - 297
• Main Authors: Audrain, H., Kenward, C., Lovell, C.R., Green, C., Ormerod, A.D., Sansom, J., Chowdhury, M.M.U., Cooper, S.M., Johnston, G.A., Wilkinson, M., King, C., Stone, N., Horne, H.L., Holden, C.R., Wakelin, S., Buckley, D.A.
• Format: Journal Article
• Language: English
• Published: Oxford Blackwell Publishing Ltd 01.08.2014; Wiley-Blackwell
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Allergens - toxicity; Biological and medical sciences; Child; Child, Preschool; Cyclohexenes - toxicity; Dermatitis, Allergic Contact - epidemiology; Dermatology; Female; Humans; Irritants - toxicity; Male; Medical sciences; Middle Aged; Monoterpenes - toxicity; Patch Tests; Perfume - toxicity; Terpenes - toxicity; United Kingdom - epidemiology; Young Adult; United Kingdom; Europe; Immunopathology; Allergy; Dermatology
• ISSN: 0007-0963; 1365-2133
• DOI: 10.1111/bjd.13037

Summary Background The oxidized forms of the fragrance terpenes limonene and linalool are known to cause allergic contact dermatitis. Significant rates of contact allergy to these fragrances have been reported in European studies and in a recent worldwide study. Patch testing to oxidized terpenes is not routinely carried out either in the U.K. or in other centres internationally. Objectives To investigate the prevalence of contact allergy to oxidized limonene and linalool in the U.K. Methods Between 1 August 2011 and 31 December 2012, 4731 consecutive patients in 13 U.K. dermatology departments were tested for hydroperoxides of limonene 0·3% pet., hydroperoxides of linalool 1·0% pet., stabilized limonene 10·0% pet. and stabilized linalool 10·0% pet. Doubtful (?+) and equivocal (±) reactions were grouped together as irritant reactions. Results Two hundred and thirty‐seven patients (5·0%) had a positive patch test reaction to hydroperoxides of limonene 0·3% pet. and 281 (5·9%) to hydroperoxides of linalool 1·0% pet. Irritant reactions to one or both oxidized terpenes were found in 242 patients (7·3%). Eleven patients (0·2%) had a positive patch test reaction to the stabilized terpenes alone. Conclusions This large, multicentre U.K. audit shows a significant rate of allergy to the hydroperoxides of limonene and linalool plus a high rate of irritant reactions. Testing to the oxidized forms alone captures the majority (97·0%; 411 of 422) of positive reactions; testing to nonoxidized terpenes appears to be less useful. We recommend that the hydroperoxides of limonene and linalool be added to an extended baseline patch test series. What's already known about this topic? Limonene and linalool auto‐oxidize upon exposure to air and their oxidation products can cause contact allergy. A significant rate of allergy to oxidized limonene and linalool has been shown in multicentre European studies and one small, single‐centre U.K. study. What does this study add? This is the first multicentre audit to show a significant rate of allergy to oxidized terpenes throughout the U.K. There is a high rate of irritant reactions to the oxidized terpenes. We recommend that oxidized limonene and linalool be added to an extended baseline patch test series in the U.K. The optimum concentration of the terpene hydroperoxides for patch testing has yet to be determined.