Background: Ethylenediamine dihydrochloride is a versatile aliphatic amine found in numerous medications and industrial compounds and is a known sensitiser. The sensitization prevalence is affected by geographical and socio-cultural factors. Objectives: The objectives are to analyse the temporal trend of sensitization to ethylenediamine dihydrochloride in northeastern Italy and to investigate associations with occupations. Methods: Between 1996 and 2021, 30 629 patients with suspected allergic contact dermatitis were patch tested with the Triveneto baseline series. Individual characteristics were collected through a standardised questionnaire. Results: The overall prevalence of ethylenediamine dihydrochloride sensitization was 1.29% with percentages similar in both sexes. We observed a significant decreasing trend over time (p < 0.001), yielding a sensitization prevalence <1% in recent years. Among departments, residence in Pordenone area was protective for sensitization. No significant associations were observed with specific occupations. We found significant associations between ethylenediamine dihydrochloride sensitization and being 26-35 years old (odds ratio [OR], 1.47; 95% confidence interval [CI]: 1.05-2.08), and sensitization for many haptens, such as paraben mix (OR, 5.3; 95% CI: 3.3-8.5), epoxy resin (OR, 5.1; 95% CI: 3.0-8.7), neomycin sulphate and mercaptobenzothiazole. Conclusions: Our study showed a downward time trend of ethylenediamine dihydrochloride sensitization in northeastern Italian population and pointed to an update of the Triveneto baseline series.
