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

Abstract

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.

Nickel and cobalt: Underestimated contact allergens in hairdressers?

“…Recent nickel and cobalt spot testing took place in the North German hairdressing trade [ 4 , 5 ]. In 2019, metallic working tools (scissors, sectioning clips, hair rollers, tail combs, whisks, tweezers, and hand showers) were tested for nickel release by means of a so-called nickel detection test (nickel spot test; Chemo Nickel Test, Chemotechnique Diagnostics, Vellinge, Sweden) in two northern German states (Lower Saxony and North Rhine-Westphalia) [ 4 ].…”

“…In 2019, metallic working tools (scissors, sectioning clips, hair rollers, tail combs, whisks, tweezers, and hand showers) were tested for nickel release by means of a so-called nickel detection test (nickel spot test; Chemo Nickel Test, Chemotechnique Diagnostics, Vellinge, Sweden) in two northern German states (Lower Saxony and North Rhine-Westphalia) [ 4 ]. In 2021, metal tools (scissors, sectioning clips, hair clips, hair rollers, tail combs, tweezers, straight razors, whisks, hand showers, and crochet hooks) were tested for nickel release with a nickel spot test (Chemo Nickel Test, Chemotechnique Diagnostics, Vellinge, Sweden) and with a so-called cobalt spot test; Chemo Cobalt Test, Chemotechnique Diagnostics, Vellinge, Sweden) for cobalt release, with testing taking place in three northern German states (Lower Saxony, North Rhine-Westphalia, and Schleswig-Holstein) [ 5 ]. In both studies, hairdressing salons in the low, medium and high price segments were included in equal numbers in the investigations.…”

“…In the study from 2019, nickel release was detected in 9.2% of the metal tools tested in total (n = 229); cobalt spot testing was not performed [ 4 ]. In 2021, nickel release was found in 27.6% and cobalt release was found in 2.1% of the metal tools tested in total (n = 475) [ 5 ]. The results of the aforementioned studies concerning nickel and/or cobalt release from metallic hairdressing tools are summarized in Table 2 .…”

“…Taking into account recent data showing that both nickel and cobalt allergies are common among hairdressers, it is necessary to explore whether occupational sources of exposure should be considered as possible [ 9 , 10 ]. To the best of our knowledge, the study from 2019 considered in the present work represents the first study in which nickel release from all common metallic work tools in the hairdressing trade was investigated [ 4 ]; the study from 2021 is the first study in which, in addition to nickel spot testing, an analysis regarding cobalt release from metal tools in the hairdressing trade was also performed [ 5 ].…”

“…Moreover, in the 1990s, it was explicitly stated that there was no increased exposure to nickel in the occupational environment among hairdressers [ 3 ]. In recent field studies, release of nickel and cobalt in allergologically relevant amounts from metallic working tools in the German hairdressing trade was proven [ 4 , 5 ]. In the context of the present study, the two current field studies on nickel and cobalt release from metal tools in the German hairdressing trade will be summarized, analyzed, and evaluated.…”