The epidemic of contact allergy to methylisothiazolinone-An analysis of Danish consecutive patients patch tested between 2005 and 2019

Sensitization to isothiazolinones in the Spanish Contact Dermatitis Registry (REIDAC): 2019-2021 epidemiological situation

BACKGROUND

Current frequency and risk factors for sensitization to methylisothiazolinone (MI), methylchloroisothiazolinone/methylisothiazolinone (MCI/MI), benzisothiazolinone (BIT) and octylisothiazolinone (OIT) in Spain are not well known.

OBJECTIVES

To study the frequency of sensitization, risk factors and simultaneous sensitization between the four isothiazolinones.

MATERIALS AND METHODS

We analysed all 2019-2021 consecutive patients patch-tested with MI (0.2% aq.), MCI/MI (0.02% aq.), BIT (0.1% pet.) and OIT (0.1% pet) within the Spanish Contact Dermatitis Registry (REIDAC).

RESULTS

A total of 2511 patients were analysed. Frequencies of sensitization were: any isothiazolinone 15.7%, MI 6.8%, MCI/MI 4.8%, BIT 3.5% and OIT 0.5%. MI and MCI/MI sensitization was associated with being occupationally active, hand dermatitis, detergents and age over 40. BIT sensitization was associated with leg dermatitis and age over 40. About one in nine MI-positive patients were positive to BIT, whereas one in five BIT-positive patients were positive to MI.

CONCLUSIONS

Sensitization to MI, MCI/MI and BIT is still common in Spain, while sensitization to OIT is rare. Currently, sensitization to MI and MCI/MI seems to be occupationally related. Although its origin is unknown, sensitization to BIT is more frequent in patients aged over 40 years. Simultaneous sensitization between MI and BIT is uncommon.

Occupational hand eczema reduces career length in hairdressers: a prospective cohort study of Danish hairdressers graduating from 1985 to 2007

BACKGROUND

Occupational hand eczema (OHE) is common in hairdressers, and many leave the trade because of the disease. However, the exact impact of OHE on career length is unknown.

OBJECTIVE

To assess the effect of OHE on career length and risk factors associated with leaving the trade because of OHE in hairdressers followed-up for up to 35 years.

METHODS

A prospective cohort study of Danish hairdressers graduating between 1985 and 2007 (n=5219) was performed. A questionnaire was sent in 2009 and 2020. The Danish Labor Marked Supplementary Pension Scheme provided information on affiliation to the hairdressing profession. Career length was assessed by Kaplan-Meier analyses.

RESULTS

The median survival time was 12.0 (95% CI 11.0 to 13.0) years in graduates with OHE and 14.0 (95% CI 12.6 to 15.4) years in graduates without OHE (p<0.001). Graduates with a frequency of hand eczema (HE) of 'once', 'several times' and 'almost all the time' had a median survival time of 20.0 (95% CI 14.6 to 25.4), 12.0 (95% CI 10.7 to 13.3) and 7.0 (95% CI 5.6 to 8.4) years, respectively. Graduates with OHE that left the trade (partly) because of HE constituted 11.7% of the study population. Factors associated with leaving the trade because of HE included a history of atopic dermatitis (adjusted OR (aOR) 2.2 (95% CI 1.2 to 4.0), a history of a positive patch test (aOR 5.1 (95% CI 2.3 to 11.0) and allergy to hair dyes (aOR 9.4 (95% CI 3.4 to 25.6).

CONCLUSION

Career length is reduced in hairdressers with OHE, especially if frequently relapsing or caused by contact allergy, for example, to hair dyes.

Patch test results with the European baseline series, 2019/20-Joint European results of the ESSCA and the EBS working groups of the ESCD, and the GEIDAC

BACKGROUND

Continual analyses of patch test results with the European baseline series (EBS) serve both contact allergy surveillance and auditing the value of included allergens.

OBJECTIVES

To present results of current EBS patch testing, obtained in 53 departments in 13 European countries during 2019 and 2020.

METHODS

Anonymised or pseudonymised individual data and partly aggregated data on demographic/clinical characteristics and patch test rest results with the EBS were prospectively collected and centrally pooled and analysed.

RESULTS

In 2019 and 2020, 22 581 patients were patch tested with the EBS. Sensitization to nickel remained most common (19.8 [19.2-20.4]% positivity [95% confidence interval]). Fragrance mix I and Myroxylon pereirae yielded very similar results with 6.80 (6.43-7.19)% and 6.62 (6.25-7.00)% positivity, respectively. Formaldehyde at 2% aq. yielded almost one percentage point more positive reactions than 1% concentration (2.49 [2.16-2.85]% vs. 1.59 [1.33-1.88]); methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) and MI alone up to around 5% positives. Among the new additions, propolis was most commonly positive (3.48 [3.16-3.82]%), followed by 2-hydroxyethyl methacrylate (2.32 [2.0-2.68]%).

CONCLUSION

Ongoing surveillance on the prevalence of contact sensitization contributes to an up-to-date baseline series containing the most frequent and/or relevant contact sensitizers for routine patch testing in Europe.

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.

European patch test results with audit allergens as candidates for inclusion in the European Baseline Series, 2019/20 - Joint results of the ESSCAA and the EBSB working groups of the ESCD, and the GEIDACC

BACKGROUND

In 2019, a number of allergens (haptens), henceforth, 'the audit allergens,' were considered as potential additions to the European baseline series (EBS), namely, sodium metabisulfite, 2-bromo-2-nitropropane-1,3-diol, diazolidinyl urea, imidazolidinyl urea, Compositae mix II (2.5 or 5% pet), linalool hydroperoxides (lin-OOH), limonene hydroperoxides (lim-OOH), benzisothiazolinone (BIT), octylisothiazolinone (OIT), decyl glucoside, lauryl glucoside; Evernia furfuracea (tree moss), was additionally tested by some departments, too.

OBJECTIVES

To collect further data on patch test reactivity and clinical relevance of the audit allergens in consecutive patients across Europe.

METHODS

Patch test data covering the audit allergens in 2019 and 2020 were collected by those departments of the ESSCA testing these, as well as further collaborators from the EBS working group of the ESCD, and the Spanish GEIDAC. As patch test outcome, reactions between day (D) 3 and D5 were considered.

RESULTS

Altogether n=12403 patients were tested with any of the audit allergen. Positive reactions were most common to lin-OOH 1% pet. (8.74 (8.14-9.37)), followed by lin-OOH 0.5% pet., and lim-OOH 0.3% pet (5.41 (4.95-5.89)). Beyond these terpene hydroperoxides, BIT 0.1% pet. was the second most common allergen with 4.72 (4.2-5.28), followed by sodium metabisulfite 1% pet. (3.75 (3.32-4.23)) and Compositae mix 5% pet. (2.31 (1.84-2.87). For some allergens, clinical relevance was frequently difficult to ascertain.

CONCLUSIONS

Despite many positive patch test reactions, it remains controversial whether lin- and lim-OOH should be tested routinely, while at least the two preservatives BIT and sodium metabisulfite appear suitable. The present results are a basis for further discussion among the ESCD members and ultimately decision on their implementation into routine testing. This article is protected by copyright. All rights reserved.

Facial contact dermatitis caused by cosmetic-relevant allergens

BACKGROUND

Facial allergic contact dermatitis caused by cosmetic products is common. New allergens in cosmetics continuously emerge.

OBJECTIVES

To investigate characteristics of patients with facial dermatitis (FD) between 2010 and 2019 including patch test results from cosmetic-related allergens and a new test series with cosmetic-relevant natural ingredients (CRNIs).

METHODS

This is a retrospective study analysing demographics, clinical characteristics according to MOAHLFA index (male; occupation; atopic dermatitis; hand; leg; face; age ≥ 40 years), and patch test results to 27 cosmetic-relevant allergens in FD patients. A prospective study evaluating a screening test series with CRNIs in consecutive FD patients for 1 year was also conducted. These patients received a questionnaire for collecting extra characteristics (eg, concerning quality of life).

RESULTS

Of 8740 tested patients, 2292 (26.2%) had FD. Of these, 30.6% had cosmetic-induced FD. The most common cosmetic-related allergens were fragrances and preservatives. The most common patch test-positive CRNIs were hydroperoxides of limonene and linalool, and propolis. Potato and peanut were rare, but the most common prick test-positive CRNIs, however, without any relation to the use of cosmetic products. FD affected nearly all patients' quality of life and caused limitations to their daily life.

CONCLUSIONS

Updated management and quick diagnosis of FD is important to avoid negative impact on patients' quality of life.

Evolution of methylisothiazolinone sensitization: a Belgian multicentric study from 2014 to 2019

BACKGROUND

In the 2010s an epidemic of allergic contact dermatitis to methylisothiazolinone occurred in Europe. European authorities banned the use of methylisothiazolinone in leave-on cosmetics in 2017 and limited its use in rinse-off products in 2018.

OBJECTIVES

To investigate the sensitization rate to methylisothiazolinone in Belgium between January 2014 and December 2019, and to assess co-sensitizations to octylisothiazolinone and benzisothiazolinone in methylisothiazolinone -sensitized patients.

METHODS

A retrospective study of patch test results with methylisothiazolinone, octylisothiazolinone and benzisothiazolinone observed in patients attending five Belgian hospitals.

RESULTS

Overall, 560 of 10.029 patients (5.58%) had a positive patch test reaction to methylisothiazolinone, and its sensitization rate decreased from 7.9% in 2014 to 3.1% in 2019. Rinse-off cosmetics, paints and detergents were the most prevalent sensitization sources in recent years. Simultaneous reactions readily occurred to octylisothiazolinone, and, surprisingly, and increasingly, also to benzisothiazolinone.

CONCLUSIONS

Contact allergy to methylisothiazolinone in Belgium has reached a pre-epidemic level, reflecting the impact of recent regulatory measures. Leave-on cosmetics, in contrast to rinse-off products, have almost disappeared as sensitization sources in Europe. Paints and detergents also remain problematic. The remarkably high number of patients (co-) sensitized to benzisothiazolinone should be a focus of future research. This article is protected by copyright. All rights reserved.

No immediate effect of regulatory reduction of chromium in leather among adult patients with chromium allergy

BACKGROUND

In March 2014, the European Commission issued a new regulation restricting the content of hexavalent chromium (Cr) in leather to no more than 3 mg/kg. We previously performed a questionnaire study in January 2014 to characterize our patients with Cr contact allergy prior to regulatory intervention.

OBJECTIVES

To assess whether clinical characteristics, self-reported sources of Cr exposure, and burden of disease changed in patients with Cr allergy over time.

METHODS

A questionnaire study was performed among 172 adult dermatitis patients with Cr allergy and 587 age- and sex-matched dermatitis patients without Cr allergy. A questionnaire was sent to all dermatitis patients patch tested from 2003 to 2018 in August 2019.

RESULTS

The overall response rate was 61.2% (759/1241). Patients with Cr allergy were still more commonly affected by current foot dermatitis (odds ratio [OR] 3.82, 95% confidence interval [CI] 2.07-7.08) and hand dermatitis (OR 1.98, 95% CI 1.13-3.49) compared with controls diagnosed during 2013 to 2018. The proportion of patients with Cr allergy reporting dermatitis caused by leather exposure did not change during 2003 to 2012 vs 2013 to 2018 (71.0% vs 66.2%, P = .5). Furthermore, estimates on occupational performance and disease severity (eg, current dermatitis), number of anatomical locations with dermatitis, worst-case dermatitis, and effect on work were similar in patients with Cr allergy for 2003 to 2012 vs 2013 to 2018.

CONCLUSION

No immediate sign of improvement was found in patients with Cr allergy concerning severity of disease and dermatitis from leather exposures 5 years after adoption of the regulation against hexavalent Cr in leather. The regulation may have to be revised for better protection of those already sensitized.