Patch testing hydroperoxides of limonene and linalool in consecutive patients—Results of the IVDK 2018–2020

Abstract

Background Hydroperoxides of limonene (Lim‐OOHs) and linalool (Lin‐OOHs) are potent contact sensitizers. Objectives To investigate the prevalence of positive patch test (PT) reactions to Lim‐OOHs and Lin‐OOHs in consecutive patients, their demographic factors and concomitant reactions. Methods Between 7/2018 and 12/2020, Lim‐OOHs 0.3% pet. and Lin‐OOHs 1% pet. were patch tested in 5511 consecutive patients. We assessed PT reactivity and analysed data from patients with either positive or negative PTs to Lim‐OOHs and Lin‐OOHs. Results Positive PT results to Lim‐OOHs (n = 170, 3.1%) and Lin‐OOHs (n = 483, 8.8%) were frequent. Most of the positive reactions were weak (LimOOHs n = 134/LinOOHs n = 429), and even more frequently, doubtful (n = 252/n = 578) or irritant reactions (n = 81/n = 178) were documented. PT reactivity to Lim‐OOHs and Lin‐OOHs was increased in patients with irritant reactions to sodium lauryl sulphate (SLS). The proportion of leg dermatitis and concomitant positive reactions to fragrances and essential oils was increased in patients with reactivity to these hydroperoxides. Conclusion The observed reaction pattern suggests that both test preparations display an irritant potential with an increased risk of false positive reactions. Preparations should be chemically monitored in order to reduce irritancy. Mindful interpretation of PT results and aimed patch testing of lower concentrations is recommended.

Occlusion of sensitizers in the baseline series for 48 h detects more contact allergy than occlusion for 24 h

“…3,4,7,8 Explanations might be that the testing with two occlusion times has not been in the same patients, 4 no defined doses in mg/cm 2 or μL/cm 2 have been used, or a too low power. 3,7,8 Interestingly, a recent study with patch testing with oxidized terpenes in more than 5000 patients at different German and Austrian clinics demonstrated a significantly higher contact allergy rate at clinics using occlusion for 48 h as compared to 24 h. 9 Obviously, to draw robust conclusions on which occlusion time to be used, the testing with the two occlusion times should be performed simultaneously in the same patient. 3,7,8 To elicit a positive (allergic) patch test reaction, enough molecules considering the individual degree of sensitivity (weak, modest, strong contact allergy) must enter the skin within the occlusion time.…”

Work-Related Hand Eczema in Healthcare Workers: Etiopathogenic Factors, Clinical Features, and Skin Care

“…Limonene and linalool hydroperoxides, for example, were found in sterilium and other hydroalcoholic solutions. European consumer protection policies reflect research results, as EU directives and regulations require, for instance, that all cosmetic products comprised of more than 0.01% of certain fragrance allergens label these ingredients; prohibit lyral, atranol, and chloroatranol; and restrict the use of cancer-causing methyl eugenol [92,95].…”