Trends and current spectrum of contact allergy in Central Europe: Results of the Information Network of Departments of Dermatology (IVDK), 2007 - 2018.

Changing patterns of exposure lead to changes in the spectrum of contact allergy in the population and in patients patch tested for suspected contact allergy. The main contact allergens (haptens) are assembled in the so-called baseline series.To present the current spectrum of contact allergy to baseline series allergens and its temporal development over the last 12 years collected in the 56 active departments of the tri-national Information Network of Departments of Dermatology (IVDK).Patch test data along with core demographic and clinical information, subdivided into periods of all patients patch tested with the baseline series in the IVDK were descriptively analysed. Moreover, log-binomial regression analysis addressed temporal trends of specific contact allergies, adjusted for potentially confounding factors.Among the 125436 patients tested with the German baseline series, the most common allergens were nickel (14.7%), fragrance mix I (8.1%), Myroxylon pereirae resin (7.5%) and cobalt (5.2%), with no conclusive trend. The rise and fall, following (self) regulation in the EU of contact allergy to methylchloroisothiazolinone/ methylisothiazolinone (MI) reflected the MI contact allergy epidemic. Propolis showed a marked upward trend with a prevalence of 3.94% in the period 2015-2018.Decreases in sensitisation prevalence likely reflect reduced exposure, with some lag, as for hydroxyisohexyl 3-cyclohexene carboxaldehyde. If no (sufficient) decrease can be observed despite interventions, such as for nickel and chromium, affected subgroups should be identified and their causative exposures explored. Finally, increases like observed with propolis certainly warrant targeted investigation of exposures driving sensitisation, and possibly intervention.