Contact Allergy Cross-reactions: Retrospective Clinical Data and Review of the Literature

Cross-Reactivity Between Propylene Glycol and Butylene Glycol

Background: Propylene glycol (PG) and butylene glycol (BG) are not known to be cross-reactors. However, no large-scale studies have assessed the cross-reactivity rate (CRR) between these 2 structurally and functionally similar compounds. Objectives: The aim of this study was to determine whether PG and BG demonstrate cross-reactivity. Methods: This is a retrospective chart review of 893 patients who underwent patch testing for both PG and BG from 2020 to 2022. The frequencies of positive reactions and concomitant reaction rates were calculated. Results: In our cohort, 53 (5.94%) patients reacted to PG and 13 patients (1.46%) reacted to BG. Of the patients who reacted to PG, 6 reacted to BG representing a CRR of 11.3%, whereas the CRR to PG in BG-allergic patients was 46.2%. Conclusions: For those allergic to BG, PG should be considered a cross-reactor. This relationship is somewhat unidirectional, as patients allergic to PG demonstrated a CRR to BG of only 11.3%, significantly lower than the 46.2% CRR to PG among BG-allergic patients.

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.

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.

Trends in formaldehyde and formaldehyde-releaser contact allergies as compared with market exposure in Thailand

BACKGROUND

Formaldehyde and formaldehyde releasers (FRs) are common preservatives in cosmetics and household products. Their contact allergy trends are decreasing in Europe and America, but trend data for Asia are limited.

OBJECTIVES

The first objective was to determine the prevalences of and trends in contact allergies to formaldehyde and FRs. The second objective was to establish how often formaldehyde and FRs were mentioned on the labels of products sold in the Thai market.

METHODS

Twenty years of data on patch test results for formaldehyde and FRs were reviewed. Their frequency of mention on the labels of 5855 products was analyzed.

RESULTS

The trends in contact allergy to formaldehyde and FRs were decreasing. The overall prevalence of formaldehyde contact allergy was 2.5%. The most common FR to cause contact allergy was quaternium-15. Formaldehyde and FRs were identified as ingredients in 10.2% of the products surveyed. Dimethylol dimethyl hydantoin was the most common FR (5.2%). The highest use of formaldehyde and FRs (15.5%) was in hair care products.

CONCLUSIONS

Although contact allergy trends in Thailand were decreasing, the proportion of products with FRs remained high. Comprehensive and universal legislation is needed to control the presence of formaldehyde and FRs. This article is protected by copyright. All rights reserved.

Patch testing with glucosides: The North American Contact Dermatitis Group experience, 2009-2018

BACKGROUND

Alkyl glucosides are nonionic surfactants that are increasingly used in personal care products.

OBJECTIVE

To characterize positive patch test reactions to decyl glucoside (5% petrolatum, tested 2009-2018) and lauryl glucoside (3% petrolatum, tested 2017-2018).

METHODS

Retrospective analysis of patients tested by the North American Contact Dermatitis Group.

RESULTS

Of 24,097 patients patch tested to decyl and/or lauryl glucoside, 470 (2.0%) had positive reactions. Compared with glucoside-negative patients, glucoside-positive patients had higher odds of occupational skin disease (13.4% vs 10.1%; P = .0207), history of hay fever (38.5% vs 31.6%; P = .0014), atopic dermatitis (39.0% vs 28.6%; P < .0001), and/or asthma (21.8% vs 16.5%; P = .0023). Most glucoside reactions (83.9%) were currently relevant. The most common source was personal care products (63.0%), especially hair products (16.5%) and skin cleansers (15.2%). Of 4933 patients tested to decyl and lauryl glucoside, 134 (2.7%) were positive to 1 or both; 43.4% (43 of 99) of decyl-positive patients were also positive to lauryl glucoside and 55.1% (43/78) of lauryl glucoside patients were also positive to decyl glucoside.

LIMITATIONS

The cohort predominantly reflects a referral population, and follow-up after testing was not captured.

CONCLUSION

Glucoside positivity occurred in 2.0% of the tested patients. Reactions were often clinically relevant and linked to personal care products. Cross-reactivity was >40%.