Contact allergy to oxidized linalool and oxidized limonene: Patch testing in consecutive patients with dermatitis

Results of patch testing with five fragrance materials hitherto not tested: A dose-finding study in the clinical population

BACKGROUND

Quantitative risk assessment (QRA) for skin sensitization is used to derive safe use levels of sensitising fragrance ingredients in products. Post-marketing surveillance of the prevalence of contact allergy to these ingredients provides relevant data to help evaluate the performance of these measures.

OBJECTIVES

To determine a suitable patch test concentration for five fragrance materials that had hitherto not been tested on a regular basis. These concentrations are then to be used in a surveillance study with patch testing consecutive patients over an extended monitoring period.

MATERIALS AND METHODS

Furaneol, CAS.3658-77-3; trans-2-hexenal, CAS.6728-26-3; 4,8-dimethyl-4,9-decadienal, CAS.71077-31-1; longifolene, CAS.475-20-7; benzaldehyde, CAS.10052-7, were patch tested with other fragrance allergens in four clinics. Patch testing was conducted in three rounds, starting with the lowest concentrations of the five ingredients. The doses were increased in the subsequent rounds if no late-appearing positive reactions and virtually no irritant reactions were reported.

RESULTS

Overall, 373 patients were tested. No positive allergic reaction was reported to the five ingredients. Patch test results of other fragrance allergens are reported.

CONCLUSIONS

The highest test concentrations are each considered safe for patch testing consecutive patients. Further surveillance based on these preparations will evaluate the hypothesis that QRA-driven consumer product levels of these fragrances can prevent sensitization.

Contact allergy in Swedish professional ice hockey players

BACKGROUND

Professional ice hockey players may contract irritant and allergic contact dermatitis.

AIMS

To investigate the presence of contact allergy (CA) in professional ice hockey players in Sweden.

METHODS

Ten teams from the two top leagues were assessed for potential occupational exposure to sensitizers. Exactly 107 players were patch tested with an extended baseline series and a working series, in total 74 test preparations. The CA rates were compared between the ice hockey players and controls from the general population and dermatitis patients.

RESULTS

One out of 4 players had at least one contact allergy. The most common sensitizers were Amerchol L 101, nickel and oxidized limonene. CA was as common in the ice hockey players as in dermatitis patients and significantly more common than in the general population. Fragrances and combined sensitizers in cosmetic products (fragrances + preservatives + emulsifier) were significantly more common in ice hockey players compared with the general population.

CONCLUSION

The possible relationship between CA to fragrances and cosmetic products on the one hand and the presence of dermatitis on the other should be explored further.

Allergic Contact Dermatitis to Linalool Hydroperoxides: Pitfalls in the Diagnostic Process-Findings from a Repeated Open Application Test Study

Background: Increasing trends of oxidized linalool contact allergy have been reported. However, the impact of reactivity and dose in eliciting allergic contact dermatitis caused by linalool hydroperoxides is insufficiently investigated. Objectives: To perform repeated open application tests (ROATs) using the real-world concentrations of linalool hydroperoxides in patients and control participants. Materials and Methods: Patients who previously had a positive (patients) and a negative (controls) patch test reaction to linalool hydroperoxides 1.0% in petrolatum were patch tested with a dilution series of linalool hydroperoxides preparations and asked to perform ROAT twice daily with 3 concentrations of linalool hydroperoxides creams and a negative control cream for 28 days. The creams contain 44, 140, and 440 PPM of linalool hydroperoxides, representing real-world doses reported in consumer products. Results: Of all 47 participants, 31 were linalool hydroperoxides contact allergy patients, and 16 were controls. One patient had a positive ROAT reaction in the area where cream at the highest concentration of linalool hydroperoxides was applied for 28 days. Conclusions: Repeated exposure to creams containing linalool hydroperoxides at real-life concentrations could rarely elicit an allergic reaction on intact skin after 4 weeks.

Patterns of simultaneous contact allergies in patients with contact sensitization to oxidised linalool and oxidised limonene

BACKGROUND

Contact allergy rates of linalool and limonene hydroperoxides (HPs) have increased.

OBJECTIVES

To demonstrate the patterns of simultaneous positive patch test (PT) reactions and prevalences of multiple contact allergies (MCAs) in patients with contact allergy to linalool and/or limonene HPs.

METHODS

A retrospective analysis of consecutive dermatitis patients in 2015-2020 was performed.

RESULTS

Of all 4192 patients, 1851 had at least one positive PT reaction. Of these, 410 (22.2%) had MCAs, significantly related to a higher age (p-value = 0.003). Patients with an exclusively positive reaction to linalool HPs but not limonene HPs were shown to have MCAs (p-value <0.001, odds ratio (95% confidence interval) = 4.15 (3.01-5.73)). Patients with simultaneous contact allergies to both linalool and limonene HPs had contact allergies to many other screening and fragrance allergens.

CONCLUSIONS

Simultaneous positive PT reactions to allergens in baseline series and fragrances are common in patients with the HPs contact allergy, especially linalool HPs. The pattern of simultaneous PT reactions principally suggested the co-sensitization of the cosmetic allergens.

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

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.

North American Contact Dermatitis Group Patch Test Results: 2019-2020

Background: Patch testing is an important diagnostic tool for assessment of allergic contact dermatitis (ACD). Objective: This study documents the North American Contact Dermatitis Group (NACDG) patch testing results from January 1, 2019, to December 31, 2020. Methods: At 13 centers in North America, patients were tested in a standardized manner with a screening series of 80 allergens, and, as indicated, supplemental allergens. Results: Overall, 4121 patients were tested; 2871 (69.7%) had at least 1 positive/allergic patch test reaction and 2095 patients (51.2%) had a primary diagnosis of ACD. The most commonly positive allergens were nickel (18.2%), methylisothiazolinone (MI) (13.8%), fragrance mix (FM) I (12.8%), hydroperoxides of linalool (HPL) (11.1%), and benzisothiazolinone (BIT) (10.4%). Compared with that of 2017-2018, prevalence of top 20 allergens statistically increased for FM I, HPL, BIT, propolis, and hydroperoxides of limonene (3.5%). For the first time, MI positivity did not increase between reporting periods. Approximately one-fifth of patients (20.3%) had ≥1 clinically relevant reaction(s) to allergens/substances not on the NACDG series. Conclusions: The epidemic of MI contact allergy in North America may have reached a plateau. Patch testing using a robust screening series, and supplemental allergens as indicated, is necessary for comprehensive evaluation of ACD.

Use of sorbitan sesquioleate in patch test preparations and patch testing with the substance-What do our results mean?

BACKGROUND

Sorbitan sesquioleate (SSO) is a sorbitan fatty acid ester, an emulsifier used in topical products and certain patch test preparations. SSO may affect the patch test results. It has been debated whether to include the substance in the baseline series to avoid misinterpretation of the results.

OBJECTIVES

To report the prevalence and simultaneous reactions of SSO with other patch test preparations containing SSO as an emulsifier.

MATERIALS AND METHODS

A retrospective analysis of 3539 dermatitis patients who underwent patch testing from 2016 to 2020 was performed.

RESULTS

The 5-year SSO contact allergy prevalence was 0.48%, and 1.3% had a doubtful reaction. Patients with a stronger positive reaction (2+, 3+) were more likely to react simultaneously to other allergen preparations containing SSO (p value = 0.018). One patient with a strong reaction to SSO reacted positively to all SSO-containing patch test preparations. Definite fragrance allergens could not be identified in the patients who had simultaneous reactions to SSO and fragrance mix (FM) I.

CONCLUSIONS

Patch testing with allergen preparations containing SSO affected the patch test interpretation. Fragrance contact allergy could not be ruled out when a patient simultaneously reacted to SSO and FM I. Changing emulsifiers in patch test preparations would be advantageous.

Increased rates of fragrance allergy in fibromyalgia individuals tested with the Swedish baseline patch test series

BACKGROUND

Contact allergy can manifest in a variety of ways clinically. Systemic contact allergy may occasionally present with pain in muscles and joints. Fibromyalgia is a chronic rheumatic disease characterized by pain and with virtually unknown aetiology.

OBJECTIVES

The aim of this study was to investigate the contact allergy rates to the sensitizers in a baseline series and compare with corresponding rates in dermatitis patients and the general population.

METHODS

Patch testing with the Swedish baseline series was performed in 120 individuals with fibromyalgia. Fisher's exact test was used for pair-wise comparisons of contact allergy rates between the fibromyalgia group and two control groups, dermatitis patients and individuals in the general population.

RESULTS

Contact allergy was significantly more common in the fibromyalgia group compared to the general population concerning nickel and the fragrance markers Myroxolon pereirae and fragrance mix I. There were fewer allergic reactions to preservatives in the fibromyalgia group compared with the dermatitis group.

CONCLUSIONS

Myroxolon pereirae and fragrance mix I represent besides fragrance allergy also allergy to flavouring substances which indicate that oral exposure to flavouring substances and hygiene products might be important for sensitization and possibly elicitation of systemic contact allergy symptoms in fibromyalgia individuals.

Contact sensitization to essential oils: IVDK-data of the years 2010 - 2019

BACKGROUND

Essential oils (EOs) are widely used in cosmetics, perfumes, massage fluids, aroma therapy, and natural medicine. Some essential oils contain contact sensitizers.

OBJECTIVES

To describe the frequency of sensitization to EOs in dermatitis patients presenting in skin clinics including concomitant reactions, to evaluate the EO patch test preparations, and to identify patient groups with an increased risk of EO sensitization.

PATIENTS AND METHODS

Retrospective analysis of data from the Information Network of Departments of Dermatology (IVDK), 2010-2019.

RESULTS

Twelve EOs were patch tested in an aimed manner in 10 930 patients, of whom 908 (8.3%) reacted to at least one EO. Only 6 EOs elicited more than 1% positive patch test reactions: ylang ylang (I + II) oil (3.9%), lemongrass oil (2.6%), jasmine absolute (1.8%), sandalwood oil (1.8%), clove oil (1.6%), and neroli oil (1.1%). Concomitant reactions among EOs or to EOs and fragrances were frequent. Among EO-positive patients, women, leg dermatitis patients, patients aged 40 years or more, masseurs and cosmeticians were over-represented.

CONCLUSIONS

Sensitization to EOs occurs, albeit infrequently in most cases. Masseurs and cosmeticians have an increased risk of sensitization to EOs. This article is protected by copyright. All rights reserved.

Novel insights into contact dermatitis

Contact dermatitis is a common disease, caused by repeated skin contact to contact allergens or irritants, resulting in allergic contact dermatitis (ACD) and/or irritant contact dermatitis. Attempts have been made to identify biomarkers to distinguish irritant and allergic patch test reactions, which could aid diagnosis. Some promising candidates have recently been identified, but verification and validation in clinical cases still need to be done. New causes of ACD are constantly recognized. In this review, 10 new contact allergens from recent years, were identified, several relating to anti-age products. Frequent allergens causing considerable morbidity in the population such as the preservative methylisothiazolinone (MI) have been regulated in EU. A significant drop in cases has been seen, while high rates are still occurring in other areas such as North America. Other frequent causes are fragrance allergens especially widely used terpenes and acrylates used in medical devises for control of diabetes. These represent unsolved problems. Recent advances in immunology have opened for a better understanding of the complexity of contact dermatitis, especially ACD. The disease may be more heterogenous that previous understood with several subtypes. With the rapidly evolving molecular understanding of the disease, the potential for development of new drugs for personalized treatment of contact dermatitis is considerable.

Simultaneous patch testing with fragrance markers in the baseline series and the ingredients of fragrance mixes ‐ an update from southern Sweden

Background

Regularly updating the prevalence of fragrance contact allergy (CA) is important. Patch testing with fragrance markers in the baseline series and the ingredients of fragrance mixes (FMs) is still debated.

Objectives

To update the prevalence and clinical characteristics of patients with fragrance CA. To establish the results of patch testing with individual allergens of FMs.

Methods

A retrospective analysis of 3539 patients with dermatitis who were patch tested with the baseline series and FMs ingredients during 2016 to 2020 was performed.

Results

The prevalence of fragrance CA was 13%. About 10% of these patients with fragrance CA would be missed if the individual ingredients were not tested. Unlike hydroxyisohexyl 3‐cyclohexene carboxaldehyde, there was no decreasing trend of CA to Evernia prunastri (oakmoss) extract after the EU regulation came into force. Patients with CA from only one ingredient of the mixes or having a weak positive reaction to the ingredients were significantly missed when tested with only the fragrance markers in the baseline series.

Conclusions

Patch testing with individual fragrance allergens is crucial for experts to expand knowledge in the fragrance CA field. The concentrations of the allergens in FMs may need to be adjusted to detect patients with fragrance CA, since some were significantly overlooked.

Limonene and linalool hydroperoxides review: pros and cons for routine patch testing

Limonene and linalool are among the most common fragrance terpenes used in products of everyday life. They are pre-haptens forming hydroperoxides (Lim-OOHs, Lin-OOHs) upon oxidation inducing frequent positive patch test reactions in patients with dermatitis. Still, they are not yet routinely tested in Europe. This review evaluates the patch testing experience with Lim-OOHs and Lin-OOHs by answering key questions such as whether hydroperoxide patch testing is warranted, understand difficulties or challenges related to the reading and interpretation of hydroperoxide patch test results with currently available material, assessing their relevance. Studies are increasingly pointing out to high percentages of positive reactions in patients consecutively patch tested with these oxidized products. An association between a positive clinical history and a strong patch test reaction has been described, but problems with doubtful/irritant reactions have also been reported. Considering the high frequencies of relevant positive reactions, the incorporation of Lim-OOHs 0.3% and Lin-OOHs 1% in the baseline series could be discussed and is maybe justified. Since exposure, sensitization and elicitation limits of Lim-OOHs and Lin-OOHs in the products still need to be better determined, an assessment of previous exposure, possible sensitizations and reactions may help to improve the clinical assessment. This article is protected by copyright. All rights reserved.