Fragrance- and Botanical-Related Allergy and Associated Concomitant Reactions: A Retrospective Analysis of the North American Contact Dermatitis Group Data 2007–2016

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.

Polysensitization in the Spanish Contact Dermatitis Registry (REIDAC): A 2019-2022 prospective study with cluster and network analysis

BACKGROUND

There is still limited clinical-practice data on specific clinical and patch test features, as well as on allergen clusters in polysensitization (PS).

OBJECTIVES

To determine the frequency, relevance, symptoms duration and risk factors in polysensitized patients and to assess possible allergen aggregation.

METHODS

Prospective multicentric study (January 2019-December 2022) conducted in setting of the Spanish Contact Dermatitis Register (REIDAC). Clinical and patch test data of polysensitized and oligosensitized patients were compared, and risk factors of PS were investigated with logistic multivariate regression. Unsupervised hierarchical clustering and network analysis were used to study allergen aggregation in PS.

RESULTS

A total of 10,176 patients were analysed. PS was found in 844 (8.3%). Current relevance was significantly higher in polysensitized patients (p < 0.01). Risk factors for PS were atopic dermatitis (OR: 1.58, 95% CI: 1.24-2.02), age (≥60 years vs. ≤24 years, OR: 1.75, 95% CI: 1.25-2.44) and some special locations (legs vs. face OR: 1.54, 95% CI: 1.05-2.25, hands vs. face OR: 1.46, 95% CI:1.15-1.85, arms vs. face OR: 1.49, 95% CI:1.01-2.20, trunk vs. face OR: 1.40, 95% CI:1.06-1.85). Cluster and network analyses revealed specific-allergen clusters and significant associations, including allergens belonging to metals group, fragrances and botanicals group, topical drugs group, rubber allergens and biocides.

CONCLUSIONS

This study confirms that PS is structured by discernible patterns of specific-allergen clusters and reinforces significant allergen associations in PS. Cross-reactivity and/or concomitant sensitization could explain the formation of allergen clusters in PS.

A botanical reference set illustrating a weight of evidence approach for skin sensitization risk assessment

Recent years have seen an increase in the use of botanicals and natural substances (BNS) in consumer products such as cosmetics and household care products. Most work conducted to date to assess botanicals for human safety has focused their use as dietary supplements and thus on systemic toxicity. However, the induction of skin sensitization is a possible adverse effect of natural products in particular those that come into skin contact, especially for cosmetics that remain on the skin and are not rinsed off following use. Assessments of BNS ingredients are often challenging for a number of reasons: the BNS are complex mixtures that can be of mostly unknown composition; the composition can be highly variable even within the same plant species and dependent on how processed; the physical form of the BNS raw material can vary from a highly concentrated powdered extract to a liquid extract containing only a small percentage of the BNS; testing of the BNS raw materials in New Approach Methods (NAM) has uncertainty as these methods are often not developed or validated for complex mixtures. In this study, a reference set of 14 selected BNS which span the range of skin sensitization potential was complied. These data were used in a Weight of Evidence (WoE) approach to evaluate their skin sensitization potential with each of the data rich BNS being classified as either having strong evidence of inducing skin sensitization based on human topical use history, animal data, clinical data, composition data and NAM data, or having some but more limited (weak) evidence of inducing skin sensitization, or having strong evidence of no skin sensitization potential. When available data have sufficient potency related information, sensitization potency assessment is also provided based on WoE, classifying these BNS as either strong, moderate, or weak sensitizers, or non-sensitizers. An outline for a BNS skin sensitization risk assessment framework is proposed starting with exposure-based waiving and WoE assessment for higher exposures. In addition to demonstrating the application of the WoE approach, the reference set presented here provides a set of 'data rich' botanicals which cover a range of sensitization potencies that could be used for evaluating existing test methods or aid in the development of new predictive models for skin sensitization.

Results of Patch Testing to Botanicals: Review of the Mayo Clinic Experience Over 2 Decades (1997-2017)

Background: Botanicals are increasingly incorporated into skincare products. Although allergic contact dermatitis due to botanicals is recognized, data describing the prevalence of positive patch tests to botanicals are sparse. Objective: To report the Mayo Clinic experience of patch testing to selected botanical products in the standard, extended standard, fragrance, and plant series. Methods: IRB-approved retrospective study of the Mayo Clinic experience with patch testing to botanicals from 1997 to 2017. Results: In total, 12,169 people were patch tested to botanicals in the standard, extended standard, fragrance, and plant series; 4032 were men and 8137 were women. The mean age of the population tested was 54 (standard deviation 17.7) years. Almost 11% (1320/12,169) of the patch-tested population exhibited positive reactions to at least 1 botanical agent. Myroxylon pereirae resin 25% was the most common positive allergen in the series. Patients who had positive reactions to at least 1 botanical agent were more (19.8%) likely to have a positive reaction to at least 1 additional botanical than those patients who did not have any positive tests. Most patients presented with generalized involvement (334) or involvement of the hands (284) or face (232). Conclusion: Physicians should be aware of the high prevalence of allergic contact dermatitis and patch test positivity associated with botanical products.

Systematic Identification of Copositivity Groups in Standard Series Patch Testing Through Hierarchical Clustering

Importance

Patients are frequently copositive for multiple allergens simultaneously, either due to chemical similarity or simultaneous sensitization. A better understanding of copositivity groups would help guide contact avoidance.

Objective

To use patient data to systematically determine copositivity groups in the Mayo Clinic Standard Series.

Design, Setting, and Participants

In this retrospective cross-sectional analysis, the Mayo Clinic patch test database was queried for pairwise copositivity rates in the 80 allergen Mayo Clinic Standard Series between 2012 and 2021. Data were collected from 3 tertiary care sites of the Mayo Clinic Contact Dermatitis Group and a total of 5943 patients were included, comprising all patients undergoing patch testing to the Mayo Clinic Standard Series allergens.

Main Outcomes and Measures

Copositivity rates between every 2 allergens in the 80-allergen Mayo Clinic Standard Series were estimated. After background correction, copositivity rates were analyzed using unsupervised hierarchical clustering to systematically identify copositivity groups in an unbiased manner.

Results

Overall, 394 921 total patches were applied to 5943 patients (4164 [70.1%] women, 1776 [29.9%] men, with a mean [SD] age of 52.3 [18.8] years ), comprising 9545 positive reactions. After background correction based on overall positivity rates, hierarchical clustering revealed distinct copositivity groups. Many were supported by prior literature, including formaldehyde releasers, cobalt-nickel-potassium dichromate, acrylates, 3-dimethylaminopropylamine-amidoamine-oleamidopropyl dimethylamine, alkyl glucosides, budesonide-hydrocortisone-17-butyrate, certain fragrances, compositae-sesquiterpene lactone mix, mercapto mix-mercaptobenzothiazole, carba mix-thiuram mix, and disperse orange-p-phenylenediamine. However, novel associations were also found, including glutaraldehyde-sorbitan sesquioleate, benzalkonium chloride-neomycin-bacitracin, bronopol-methylchloroisothiazolinone-methylisothiazolinone, and benzoic acid-iodopropynyl butylcarbamate.

Conclusions and Relevance

This retrospective cross-sectional analysis found that copositivity rates varied between allergens; allergens with extremely high positivity rates demonstrated nonspecific copositivity to multiple other allergens. Background correction based on positivity rates followed by hierarchical clustering confirmed prior known copositivity groups, contaminants and/or excipients leading to copositivity, and novel associations to guide contact avoidance.

Dimethylglycine, a methionine metabolite, participates in the suppressive effect of methionine on 1-fluoro-2,4-dinitrobenzene-induced dermatitis

Allergic contact dermatitis (ACD) is a common skin disorder caused by contact with allergens. The optimal treatment for ACD is to avoid contact with allergens. However, in some cases, avoiding exposure is not possible when the allergens are unknown. Therefore, establishing treatment methods other than allergen avoidance is important. We previously reported that the continuous administration of methionine, an essential amino acid, in a mouse model of atopic dermatitis alleviated its symptoms. In the present study, we investigated the effect of methionine on a mouse model of ACD caused by 1-fluoro-2,4-dinitrobenzene (DNFB). Differences in the effect of methionine were observed in DNFB-induced ACD model mice based on the mouse strain used. This difference was attributed to the suppression of hepatic dimethylglycine (DMG) production, which is associated with the suppression of hepatic betaine-homocysteine methyltransferase (Bhmt) expression by ACD. Although we did not reveal the mechanism underlying DMG suppression, our study suggests the presence of interactions between the liver and skin in dermatitis, such as the regulation of hepatic metabolic enzyme expression in dermatitis and the alleviation of dermatitis symptoms by the hepatic metabolism status of DMG.

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.

Low Prevalence of Fragrance Contact Allergy Among Turkish Population: A 24-Year, Cross-Sectional, Tertiary Single-Center, Retrospective Study

BACKGROUND

Limited data exist on fragrance contact allergy among Turkish population.

OBJECTIVE

The aim of this study was to investigate the frequency and characteristics of fragrance contact allergy in Turkey.

METHODS

A retrospective cohort study was conducted on 2566 patients consecutively patch tested with the European baseline series and additionally with a fragrance series (n = 358) at a tertiary referral center between 1996 and 2019.

RESULTS

One hundred sixty-three patients (6.4%) (male/female, 1.5:1) were sensitized with at least 1 fragrance allergen. Fragrance mix (FM) I was most frequently positive (3.9%), followed by Myroxylon pereirae (3.1%), FM II (2%), and hydroxyisohexyl 3-cyclohexene carboxaldehyde (0.5%), the latter exclusively positive in FM II-positive patients. Among 358 patients patch tested with a fragrance series, positive patch test reactions were observed in 38 patients, including 8 who did not react to baseline fragrance markers. Clinically relevant fragrance allergy was established in 128 patients (78.5%) from nonoccupational (72.4%) and occupational (6.1%) sources.

CONCLUSIONS

The low prevalence, the middle-aged male preponderance, and the predominant involvement of hands were unusual findings. Rose/citrus-flavored perfumes and eau de cologne, which are traditionally preferred in our country, were important elicitors of fragrance contact allergy, especially among middle-aged and older men.

Inter-rater variability in patch test readings and final interpretation using store-forward teledermatology

BACKGROUND

Data regarding teledermatology for patch testing are limited.

OBJECTIVES

Compare patch test readings and final interpretation by two in-person dermatologists (IPDs) with eight teledermatologists (TDs).

METHODS

Patch tested patients had photographs taken of 70 screening series of allergens at 48 hours and second readings. Eight TDs reviewed photos and graded reactions (negative, irritant, doubtful, +, ++, +++) at 48 hours and second readings; in addition, they coded a final interpretation (allergic, indeterminant, irritant, negative) for each reaction. TDs rated overall image quality and confidence level for each patient and patch test reaction, respectively. Percentage of TD-IPD agreement based on clinical significance (success, indeterminate, and failure) was calculated. Primary outcome was agreement at the second reading.

RESULTS

Data were available for 99, 101, and 66 participants at 48 hours, second reading, and final interpretation, respectively. Pooled failure (+/++/+++ vs negative) at second reading was 13.6% (range 7.9%-20.4%). Pooled failure at 48 hours and final interpretation was 5.4% (range 2.9%-6.8%) and 24.6% (range 10.2%-36.8%), respectively. Confidence in readings was statistically correlated with quality of images and disagreement.

CONCLUSION

For patch testing, teledermatology has significant limitations including clinically significant pooled failure percentages of 13.6% for second readings and 24.6% for final interpretation.

Patch Testing to Carvone: North American Contact Dermatitis Group Experience, 2009 to 2018

BACKGROUND/OBJECTIVES

Carvone, a flavoring agent, may cause allergic contact dermatitis. This study summarizes patch test reactions to carvone in patients tested by the North American Contact Dermatitis Group, 2009 to 2018.

METHODS

This was a retrospective analysis of patients positive to carvone (5% petrolatum). Demographics were compared with those of patients who were negative. Other analyses included reaction strength, clinical relevance, coreactivity with other fragrance/flavor allergens, and exposure sources.

RESULTS

Of 24,124 patients tested to carvone, 188 (0.78%) were positive. As compared with carvone-negative patients, carvone-positive patients were significantly more likely older than 40 years (P = 0.0284). Women (76.1%) and/or facial involvement (33.0%) were common in the carvone-positive group but not statistically different from carvone-negative patients; 73.3% (n = 138) of the reactions were currently relevant. Relevant sources were personal care products (46.3%, n = 87) and food (14.3%, n = 27). Coreactivity with other fragrance/flavor markers was present in 60.6% of carvone-positive patients, most commonly fragrance mix I (34.6%), balsam of Peru (24.5%), and cinnamic aldehyde (15.4%).

CONCLUSIONS

Ten-year prevalence of carvone sensitivity was 0.78%. Most carvone-positive patients were female, were older than 40 years, and/or had facial dermatitis. Personal care products were the most common source. Two-fifths of carvone reactions would have been missed by relying on other fragrance/flavoring allergens.