Characteristics and incidence of contact dermatitis among hairdressers in north-eastern Italy

Background: Hairdressers are at high risk of contact dermatitis (CD) due to skin exposure to numerous irritants and haptens in hair products in combination with frequent wet work. Objectives: To investigate the characteristics and incidence of CD among hairdressers in north-eastern Italy. Methods: A total of 324 hairdressers who had been examined and patch tested in north-eastern Italy from 1996 to 2016 were retrospectively identified, and compared with 9669 matched controls. Sensitization to allergens of the hairdressing series was analysed among hairdressers attending an occupational medicine clinic in Trieste, Italy. Incidence data were calculated from 1999 to 2016. Results: Sensitization to p-phenylenediamine, thiuram mix, and N-isopropyl-N'-phenyl-p-phenylenediamine was significantly associated with hairdressing and with hand/forearms dermatitis. Frequent sensitizers from hairdressing series were ammonium persulfate, toluene-2,5-diamine, and p-aminobenzene. The overall incidence of CD declined from 2003 (31.7 cases/10 000 workers) to 2016 (20.8 cases/10 000 workers). Conclusions: Sensitization to several haptens was significantly associated with hairdressing. The incidence of CD among hairdressers in north-eastern Italy has declined in recent years, but is still high. Preventive efforts are needed to reduce the burden of CD in this professional group.