Work

Ten Years of Patch Testing to Hydroperoxides of Limonene and Linalool: Prevalence, Patterns and Clinical Insights

Year: 2026

Type: article

Abstract: BACKGROUND: Limonene and linalool are widely used fragrances in cosmetic and household products. Upon air exposure, they autoxidise into potent sensitisers - hydroperoxides of limonene (Lim-OOH) and linalool (Lin-OOH). OBJECTIVES: The objective of this study is to investigate patch test reactions to Lim-OOH and Lin-OOH, and associated characteristics, reaction patterns, including doubtful reactions and co-reactivity with other fragrance allergens. METHOD: A retrospective analysis was conducted using registry data from 6719 consecutively patch-tested patients at Gentofte Hospital, Denmark (2014-2025). Doubtful reactions were clinically subclassified as erythematous, only (E) or infiltrated (I). RESULTS: The prevalence of positive patch test reactions was 1.6% for Lim-OOH and 3.1% for Lin-OOH. Positive Lim-OOH reactions were less likely in men and in patients with atopic, occupational or hand dermatitis, whilst positive Lin-OOH reactions were more likely in those > 40 years and less in atopic dermatitis. Most reactions peaked on day 3/4 and were weakly positive. Doubtful I reactions more frequently progressed to positive than doubtful E. Co-reactivity was observed between Lim-OOH, Lin-OOH and other fragrance allergens. Lower test concentrations reduced diagnostic sensitivity. CONCLUSION: Co-reactivity with other fragrance allergens supports true allergenicity. The currently recommended patch test concentrations (0.3% Lim-OOH and 1.0% Lin-OOH) seem optimal and qualify for inclusion in the European baseline series.

Source: Contact Dermatitis

DOI: 10.1111/cod.70102

Authors: Sofia Botvid, Rebekka Søgaard, Jakob Ferløv Baselius Schwensen, Jeanne Duus Johansen

Institutions: University of Copenhagen, Copenhagen University Hospital, Gentofte Hospital

Language: English

Topic: Contact Dermatitis and Allergies

Subfield: Dermatology

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: hybrid

Estimated APC paid: $5,060