Contact sensitization to hydroperoxides of limonene and linalool: Results of consecutive patch testing and clinical relevance.

Daan Dittmar,Marie L A Schuttelaar

doi:10.1111/cod.13137

Abstract

BackgroundHydroperoxides of limonene and linalool are potent sensitizers.ObjectivesTo investigate the prevalence of contact allergy to both hydroperoxides of limonene and hydroperoxides of linalool, to report clinical relevance, and to investigate patient demographics.MethodsA total of 821 patients (35.6% male, mean age 42.4 years ± 17.8 years) were consecutively patch tested with our departmental baseline series and our fragrance series, including hydroperoxides of limonene 0.3% pet. and hydroperoxides of linalool 1.0% pet. The clinical relevance was assessed for all positive reactions.ResultsPositive patch test reactions to hydroperoxides of limonene and to hydroperoxides of linalool were observed in 77 patients (9.4%, 95% confidence interval [CI]: 7.4%‐11.4%) and in 96 patients (11.7%, 95%CI: 9.5%‐13.9%), respectively; 38 of these patients (4.6%, 95%CI: 3.2%‐6.0%) reacted to both. Most reactions were considered to be possibly or probably clinically relevant (66.3% and 68.8%, respectively), and a small proportion were deemed to be of certain clinical relevance (18.2% and 19.8%, respectively).ConclusionAs compared with previous studies, high numbers of positive reactions to both hydroperoxides of limonene and hydroperoxides of linalool were observed, the majority of which were clinically relevant, supporting their inclusion in the European baseline series.

Highlights

Limonene (D-limonene) is the main ingredient of pressed oil from the peel of citrus fruits, and linalool is present in many herbs, flowers, woods, etc.[1,2]
The aim of the current study was to investigate the prevalences of contact allergy to hydroperoxides of limonene and hydroperoxides of linalool, and to characterize patients allergic to either or both hydroperoxides of limonene and hydroperoxides of linalool, with respect to patient characteristics and concomitant fragrance contact allergies
A database study was performed on all patients who were at least patch tested with both hydroperoxides of limonene 0.3% pet. and hydroperoxides of linalool 1.0% pet

Summary

Introduction

Limonene (D-limonene) is the main ingredient of pressed oil from the peel of citrus fruits, and linalool is present in many herbs, flowers, woods, etc.[1,2] Both are common ingredients in household products and cosmetics, such as hygiene products, perfumes, and detergents, as well as industrial products.[3,4] Limonene and linalool are ubiquitous fragrance terpenes with low sensitizing potential.[1,2,5] upon air exposure, oxidation occurs, during which different oxidation products are formed Of these oxidation products, the hydroperoxides are potent sensitizers. Conclusion: As compared with previous studies, high numbers of positive reactions to both hydroperoxides of limonene and hydroperoxides of linalool were observed, the majority of which were clinically relevant, supporting their inclusion in the European baseline series

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