Sensitization to, and allergic contact dermatitis caused by, colophonium in north‐eastern Italy in 1996 to 2016 with a focus on occupational exposures

Background Colophonium is a natural substance derived from Pineaceae trees. It is used in a wide range of consumer and occupational products because of its tackiness, and is a known sensitizer. Objectives To analyse the temporal trend of contact allergy to colophonium in north‐eastern Italy, and to evaluate the associations with occupations in our geographical area. Methodology From 1996 to 2016, 27 381 patients with suspected allergic contact dermatitis were patch tested in north‐eastern Italy. Individual characteristics were documented by use of a standardized questionnaire in 6 departments of dermatology or occupational medicine. Results The overall prevalence of colophonium sensitization was 1.67%; the prevalence was significantly higher in women (1.75%) than in men (1.49%). No significant differences among departments were observed. We found significant associations between colophonium sensitization and being a student (odds ratio [OR] 4.64; 95% confidence interval [CI]: 1.04‐20.6), being a farmer or fishermen (OR 3.63; 95%CI: 1.21‐10.84), being a housekeeper (OR 2.02; 95%CI: 1.08‐3.77), and being retired (OR 2.06; 95%CI: 1.08‐3.92). Conclusion Our study showed that contact allergy to colophonium is still relevant in north‐eastern Italy. The frequency of sensitization has dropped significantly over a period of 10 years, but students and farmers/fishermen still have sensitization prevalences above 3.5%. Our results are in line with European data.