Patch test concentrations (doses in mg/cm2) for the 12 non-mix fragrance substances regulated by European legislation

Clarification and Modification of the International Contact Dermatitis Research Group Classification of Patch Test Reactions on Behalf of the International Contact Dermatitis Research Group

The first ICDRG (International Contact Dermatitis Research Group) classification of patch test reactions was published in 1970. With this classification, many weak reactions were classified as allergic reactions. A second classification was therefore implemented one decade later on behalf of the ICDRG and the North American Contact Dermatitis Group. This classification was adopted by the European Society of Contact Dermatitis. Evaluation of the significance of the results of various studies on patch test reading demonstrated that a new ICDRG classification of patch test reactions was needed. A classification system should not be based on the exclusive presence/absence of papules and vesicles, i.e., the words "possibly papules/vesicles" allow for the unavoidable variation in reading among experts. Dermatologists are not reading patch test reactions in a uniform way due to lack of a clear definition of the threshold between weak allergic and doubtful reactions. A new ICDRG classification with clarifications and modifications of the old one is presented.

Fragrance Contact Allergy - A Review Focusing on Patch Testing

Fragrance materials are widely used in various types of products in daily life and many of them can be contact sensitizers. Contact allergy to fragrances has been reported to be common worldwide. Unlike other groups of contact allergens such as metals and preservatives, fragrance materials in consumer products can be present as single fragrance chemicals or in the form of mixtures known as natural complex substances. Due to the complexity of the fragrance materials and the high number of fragrance substances known to cause contact sensitization, selecting suitable materials for patch testing is challenging. Emerging fragrance markers have been additionally introduced in different baseline series for screening to enhance the rate of fragrance contact allergy detection. Moreover, there have been continual updates on basic knowledge, clinical perspectives, sources of exposure, and regulations on the use of fragrance materials. Avoiding pitfalls while performing patch testing with fragrance test materials is also crucial and should not be overlooked. Therefore, this review aims to update knowledge to provide a high-quality holistic approach to fragrance contact allergy diagnosis and management.

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.

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.

Contact allergy in children with and without atopic dermatitis: an Italian multicenter study

Background

Contact allergy and atopic dermatitis (AD) are both common inflammatory T cell‐mediated diseases and many factors may influence the prevalence of contact allergy in AD patients. In children, their possible correlation was debated with conflicting results.

Objectives

The present study aimed to assess the prevalence of contact sensitivity in children and to investigate the association with AD.

Materials and methods

A retrospective multicentre study on children aged from 0 to 14 years patch tested between January 2017 and December 2018 was performed. Children were consecutively patch tested with the SIDAPA (Società Italiana Dermatologia Allergologica Professionale Ambientale) baseline series.

Results

Among the 432 children investigated for contact allergy, 125 (28.9%) showed a positive reaction to at least one of the allergens tested, with a higher prevalence of positive patch test reactions in girls (32.3%) than in boys (25.0%). The most frequent contact allergens were nickel sulphate (10.2%), cobalt chloride (6.7%), methylisothiazolinone (3.7%), fragrance mix‐2 (3.2%), potassium dichromate (2.8%), fragrance mix‐1 (2.1%) and methylchloroisothiazolinone/methylisothiazolinone (2.1%). One‐hundred‐three children (23.8%) suffered from AD showing a higher prevalence of positive patch test (36.9%) compared to children without AD (26.4%).

Conclusions

Despite the topic being still controversial, the present study suggests a consistent prevalence of contact allergy among children with higher sensitivity rate among children with AD than without AD.

What is the added value of patch testing with 30 fragrance allergens in addition to the European baseline series?

Background

Patch testing with the fragrance allergy markers in the European baseline series (EBS) does not identify all patients with fragrance allergy. Hydroperoxides of linalool and limonene have been shown to be useful allergens in detecting fragrance sensitization.

Objectives

To evaluate the added value of testing with 30 fragrance allergens in addition to the EBS.

Methods

All patients with suspected fragrance allergy who underwent patch testing at the Amsterdam University Medical Centers between November 2019 and January 2021 to the EBS and fragrance series were included.

Results

Of 323 patients tested, 162 (50.2%) were found to be fragrance sensitized. The most sensitizing single allergens were the hydroperoxides of linalool (1.0 and 0.5% pet.) and limonene (0.3 and 0.2% pet.). Testing with the hydroperoxides of linalool and limonene identified 62 fragrance‐sensitized patients (38.3%) who could not be detected by the common fragrance markers. Of all fragrance‐sensitized patients, 21 (13.0%) would have been missed when not testing with the fragrance series.

Conclusions

Patch testing with the fragrance series in addition to the EBS is valuable. To reduce the risk of false‐negative reactions, it is advisable to test the hydroperoxides of linalool and limonene.

Highlights

Of the 323 patients with suspected fragrance allergy, 162 (50.2%) were found to be fragrance sensitized.

Testing with the hydroperoxides of linalool and limonene identified 62 fragrance‐sensitized patients (38.3%) who could not be detected by the European baseline series (EBS) fragrance markers. When not tested with the fragrance series, 21 (13.0%) of the sensitized patients would have been missed.

Routinely performing patch testing with the fragrance series in addition to linalool and limonene hydroperoxide as part of the EBS is recommended.

Changes in adhesive ingredients in continuous glucose monitoring systems may induce new contact allergy pattern

BACKGROUND

Medical devices (MD) in close skin-contact for a prolonged time, such as glucose monitoring (CGM) systems, are a risk factor for contact allergy, and there has been an increase in patients using these. Correct diagnosis demands targetted testing.

OBJECTIVES

We report a new allergen in a continuous CGM system in which the adhesive was changed. The allergy pattern of the patients diagnosed is reported.

METHODS

The three patients reported were patch tested with an MD series, own material, and possible allergens found through analysis with gas chromatography-mass spectrometry, comparing analysis from the CGM system before and after change.

RESULTS

The patients were sensitized to isobornyl acrylate (IBOA), found in previously used devices and the present CGM. Apart from IBOA, the culprit allergen was found to be 2,2'-methylenebis(6-tert-butyl-4-methylphenol) monoacrylate.

CONCLUSION

Allergic contact dermatitis due to CGM systems and insulin pumps are difficult to investigate and require chemical analysis. Because of the lack of information on substances used in the production, and when changes with MDs are initiated, it is difficult to advise patients, especially since they risk sensitization to several allergens. The use of MDs has increased and, thus, the need for collaboration between manufacturers, clinicians, and patient organizations.

S3 guidelines: Epicutaneous patch testing with contact allergens and drugs - Short version, Part 1

Epicutaneous patch testing is the diagnostic standard for the detection of allergic contact dermatitis. The present guidelines are aimed at residents and board-certified physicians in the fields of dermatology and allergology as well as other medical specialties involved in establishing the indication for patch testing and its execution in patients with contact dermatitis and other forms of delayed-type hypersensitivity. The target audience also includes other health care providers and insurance funds. Based on a systematic literature search and a formal consensus process (S3), the guidelines were developed by dermatologists in collaboration with pediatricians, occupational medicine physicians, nursing staff as well as patient representatives. The systematic methodological approach and appraisal of evidence upon which the recommendations are based are outlined in a separate method report that also contains evidence tables. The guidelines address general aspects of patch testing as well as medicolegal issues. The recommendations given relate to topics such as the indication for patch testing, informed patient consent, as well as the choice of test substances, test chambers and test site, duration of exposure, reading times and interpretation of test reactions. Furthermore, recommendations are provided with respect to endogenous and exogenous factors, specific patient groups (children, pregnant women, immunosuppressed individuals) as well as possible risks and adverse events associated with patch testing using contact allergens. Note: This publication is part 1 of the short version of the S3 guidelines for "Epicutaneous patch testing using contact allergens and drugs" (registry no. 013 - 018; date: March 20, 2019; valid until December 31, 2021). Part 2 of the short version will be published in the next issue. The long version of these guidelines can be accessed at www.awmf.org. The method report is available as online publication (https://www.awmf.org/leitlinien/detail/ll/013-018.html) and contains the evidence tables in its appendix.

Hand eczema and occupational contact allergies in healthcare workers with a focus on rubber additives

BACKGROUND

Hand eczema (HE) in healthcare workers (HCWs) is common. Besides wet work, healthcare work also implies exposure to contact allergens.

OBJECTIVES

To assess HE and contact allergy related to occupational exposures in HCWs.

METHODS

In a cross-sectional study, 311 HCWs with HE within the preceding 12 months and a control group of 114 HCWs without HE were investigated with the baseline series and a special patch test series based on substances found in the gloves, soaps, alcoholic hand disinfectants and hand creams provided at the hospitals.

RESULTS

Contact allergy to rubber additives was significantly more common in HCWs with HE (6%) than in HCWs without HE (1%, P = .02). The corresponding percentages for fragrances were 11% and 3%, respectively (P = .004). Occupational HE was found in 193 of 311 (62%) HCWs. Of these, 22 of 193 (11%) had occupational allergic contact dermatitis, including 17 with glove-related rubber contact allergy. Contact allergy to diphenylguanidine was as common as contact allergy to thiurams. Occupational contact allergy to rubber additives was significantly associated with sick-leave related to HE.

CONCLUSION

Contact allergy to rubber additives in medical gloves is the most common cause of occupational allergic contact dermatitis in HCWs. Aimed patch testing with relevant rubber additives is mandatory when HE in HCWs is investigated.

Occupational contact dermatitis caused by D-limonene

BACKGROUND

Limonene is widely used as a fragrance substance and solvent in cleansing products. Oxidized limonene is a frequent contact allergen among consumers of cosmetics, personal care products, and scented household cleaning products. Less is known about the sources of occupational exposure and occupational contact dermatitis caused by limonene.

OBJECTIVE

To report 14 patients with occupational contact allergy to limonene.

METHODS

The patients were examined in 2008-2013. An in-house preparation of oxidized limonene was patch tested as 3% and 5% in petrolatum from 2008 to August 2010, and after this as 3%, 1% and 0.3% pet. From 2012 onwards, a commercial test substance of limonene hydroperoxides was also used. We assessed the patients' occupational and domestic exposure to limonene.

RESULTS

Occupational limonene allergy was observed in workers who used limonene-containing machine-cleaning detergents and hand cleansers, and in workers who used limonene-containing surface cleaners and dishwashing liquids similar to those used by consumers. In 3 cases, the occupational limonene allergy resulted from work-related use of limonene-containing, leave-on cosmetic products.

CONCLUSIONS

Limonene is a frequent occupational sensitizer in hand cleansers and cleaning products. Occupational limonene contact allergy may also be caused by exposure to cosmetic products scented with limonene.