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

Abstract

Background Hydroperoxides of limonene and linalool are potent sensitizers. Objectives To investigate the prevalence of contact allergy to both hydroperoxides of limonene and hydroperoxides of linalool, to report clinical relevance, and to investigate patient demographics. Methods A 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. Results Positive 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). 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.

Contact Allergy—Emerging Allergens and Public Health Impact

“…Probably the "hottest" topic in the field of fragrance contact allergy is the role of terpene hydroperoxides as autoxidation products of terpenes used as fragrances, and specifically, of limonene and linalool hydroperoxides (Lim-OOHs and Lin-OOHs, respectively). These have been demonstrated to be important contact allergens when patch tested (in consecutive patients) [66][67][68], in accordance with experimental results [69]. However, hitherto there is still uncertainty regarding the quantity and eliciting role of hydroperoxides present in cosmetic products patients have actually been using.…”

Myroxylon pereiraeresin (balsam of Peru) – A critical review of the literature and assessment of the significance of positive patch test reactions and the usefulness of restrictive diets

“…The test material from Chemotechnique contains 5% sorbitan sesquioleate. The TRUE Test system appears to be less sensitive for detecting sensitivity to MP than the petrolatum‐based chamber systems …”

“…Test system appears to be less sensitive for detecting sensitivity to MP than the petrolatum-based chamber systems. 35,36 In 14 studies from the United States, 10 of which were performed by the North American Contact Dermatitis Group (NACDG), frequencies of sensitization have ranged from 6.6% to 13.7%. 5,37 Generally speaking, the rates appear to have decreased somewhat in the last decade, ranging in all NACDG studies between 7% and 8%.…”

Allergic contact dermatitis, mimicking atopic dermatitis, associated with the use of essential oils in “home‐made” cosmetics and aromatherapy diffusers

“…Linalool, a fragrance terpene present in many cosmetics and household products, and a major component of lavender, is a well-known cause of (airborne) allergic contact dermatitis. 4,8,9 We report this case to highlight that electronic ultrasonic diffusers and "home-made" cosmetics and remedies may well be overlooked allergen sources of this sensitizer. 10 Moreover, this case illustrates that patch tests need to be considered in patients with (therapy-resistant) AD, and preferably before a systemic treatment is initiated.…”