D3.39 - Allergic contact dermatitis to oxidized fragrance components: a case of sensitization to hydroperoxides of limonene

Background: Fragrances are among the most common causes of allergic contact dermatitis (ACD), terpene oxidation products being increasingly recognized as potent sensitizers. D-limonene, a widely used fragrant compound derived from citrus oil, lightly allergenic in its native form, rapidly oxidizes upon air exposure generating hydroperoxides of limonene with stronger sensitizing capacity. Patch testing with hydroperoxides of limonene may detect additional contact sensitizations missed by standard fragrance mixes.

We report the case of a 20-year-old female, without personal history of atopic dermatitis, who experienced two distinct episodes of typical ACD, one due to direct contact with a personal perfume (neither expired, nor left open for an extended period), and another due to secondary cutaneous exposure with a fragrance product, applied on a friend’s skin, probably oxidised. The patient’s product contained fragrances, hydroxycitronellal, limonene, linalool, hexyl cinnamal, coumarin, benzyl salicylate, benzyl benzoate, benzyl alcohol. She tolerates the contact and/or ingestion of foods containing aromatic components, such as cinnamon, cloves, vanilla, tomatoes, citrus peel, chocolate, and cola-type beverages. We performed patch testing with fragrance-related haptens from the European Baseline Series, along with d-limonene, hydroperoxides of limonene and linalool, and other screening haptens. This revealed a positive result to hydroperoxides of limonene 0.3% pet and negative results to d-limonene 10% pet, fragrance mix I 8% pet, fragrance mix II 14% pet, hydroperoxides of linalool 1% pet, Peru balsam 25% pet. A semi-open patch test with the fragrance was also negative. Moreover, although the patient presented a positive patch test to nickel sulphate hexahydrate 5% pet, she did not report any history of contact dermatitis to metal alloys used in jewellery. In addition, the plastic components with metallic finish appearance of the fragrance bottle and its atomiser were not found to release nickel according to the chemical spot test with dimethylglyoxime that we also performed.

Conclusion: This case highlights the possible clinical relevance of hydroperoxides of limonene as particular fragrance haptens in real life scenarios. Thus, we recognize the importance of including oxidized fragrance markers in a personalized patch testing workup in patients suspected of having ACD to fragrances.