Is hydroxyisohexyl 3-cyclohexene carboxaldehyde sensitization declining in central Europe?

In several studies conducted during the last decade, the synthetic fragrance hydroxyisohexyl 3-cyclohexene carboxaldehyde (HICC; CAS 31906-04-4) has been shown to be a frequent sensitizer, with a prevalence of >2% among patients tested (1–6). Recent publications, however, have reported prevalences of sensitization of <2%, both in Denmark (7) and in Germany (8). However, in the most recent re-analysis (9) of the original data from the Gentofte Hospital in Denmark (7), the declining trend was not confirmed. The present article focuses on a time trend analysis of HICC contact sensitization based on Information Network of Departments of Dermatology (IVDK) data registered between 2002 and 2011.