Exposure source for skin sensitizing hydroperoxides of limonene and linalool remains elusive: An analytical market surveillance

Abstract

Positive patch test reactions of dermatological patients to oxidized samples of linalool and limonene are frequently reported. The sensitizing ingredients in the oxidation mixtures are hydroperoxides (HP). It is not clear whether fragranced consumer products are a relevant exposure source for HP. Analytical methodologies had been validated, allowing quantification of HP in different consumer products. The analytical approach was used to analyse 104 consumer products. Samples included aged and new samples from the same brand, products suspected by patients to elicit their symptoms and products containing essential oils. Only four samples contained >50 μg/g of at least one of the HP by the screening method. Confirmatory analysis by LC-MS methods indicated that levels are even below those observed by the conservative screening method. The samples retrieved from patch-test positive patients were below detection limit for all target analytes. This market surveillance indicates that concentrations of HP in consumer products and patient products are orders of magnitude below sensitizing doses in animal tests. No evidence for hydroperoxide accumulation in aged products or products used by patients was found. The nature and source of the inducing agent responsible for the frequent positive patch test reactions to oxidized terpenes remains elusive.

Keywords: Consumer products; Market surveillance; Quantification; Skin allergy; Terpene hydroperoxides.