Decrease of contact allergy to hydroxyisohexyl 3-cyclohexene carboxaldehyde in Europe prior to its ban and diagnostic...

Area of Science:

• Dermatology
• Allergology
• Cosmetic Science

Background:

• Hydroxyisohexyl 3-cyclohexene carboxaldehyde (HICC) is a widely reported fragrance allergen.
• HICC is scheduled for prohibition in cosmetic products starting August 2021.

Purpose of the Study:

• To analyze the trend of HICC contact allergy in European patients diagnosed with dermatitis between 2009 and 2019.
• To evaluate the additional diagnostic value of separate HICC testing in baseline patch test series.

Main Methods:

• Review of patch test data from 124,472 dermatitis patients across the European Surveillance System on Contact Allergy (ESSCA) network and Herlev-Gentofte Hospital.
• Patients were patch tested with HICC 5% pet. in the baseline series between 2009 and 2019.

Main Results:

• Contact allergy to HICC was identified in 1.98% of patients in Gentofte and 1.62% in the ESSCA network.
• A significant annual decrease in HICC allergy prevalence was observed in both cohorts.
• Testing with fragrance mix II (FMII) alone would have missed 0.17% (Gentofte) and 0.35% (ESSCA) of HICC allergies.

Conclusions:

• This study provides the first evidence of a significant reduction in HICC contact allergy among European dermatitis patients.
• The observed decline is strongly correlated with the forthcoming European Union ban on HICC in cosmetics.