Experimental evaluation of nickel and cobalt release from tools and self‐reported prevalence of nickel and cobalt allergy in the German hairdressing trade.

Background: Nickel release from some metal tools in the hairdressing trade has been sporadically evidenced, whereas data about cobalt release from metal tools in the hairdressing trade are lacking. Objectives: To screen metal tools for nickel and cobalt release and to estimate the prevalence of nickel allergy and cobalt allergy in the German hairdressing trade. Methods: Four hundred seventy‐five metal tools in the hairdressing trade were tested in three North German states with a nickel spot test for nickel release and with a cobalt spot test for cobalt release. Seventy hairdressers were surveyed with a standardized questionnaire to collect data about the tested metal tools as well as the prevalence of nickel allergy and cobalt allergy. Results: One hundred thirty‐one of 475 metal tools (27.6%) – 60 of 60 hair clips (100%), five of five crochet hooks (100%), 24 of 40 tweezers (60.0%), 33 of 75 sectioning clips (44.0%), five of 32 straight razors (15.6%), and four of 45 tail combs (8.9%) – released nickel and 10 of 475 metal tools (2.1%) – three of 40 tweezers (7.5%), four of 60 hair clips (6.7%), one of 32 straight razors (3.1%), and two of 75 sectioning clips (2.7%) – released cobalt. Eight of 63 female hairdressers (12.7%) suffered from nickel allergy and two of 63 female hairdressers (3.2%) suffered from cobalt allergy. Conclusions: Metal tools in the German hairdressing trade – with which a prolonged skin contact is intended – release nickel and cobalt in allergologically relevant amounts and thus should be taken into account as occupational sources of exposure to nickel and cobalt. [ABSTRACT FROM AUTHOR]