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Occupational Exposure to Nickel and Cobalt From Hairdressing Tools: A Cross-Sectional Study in 58 Danish Salons
Kian Karimian1, Daniel Isufi2, Ulrik Ahrensbøll-Friis1,3
1Department of Dermatology and Allergy, National Allergy Research Centre, Herlev and Gentofte Hospital, University of Copenhagen, Hellerup, Denmark.
Background:
Hairdressers frequently perform wet work, which weakens the skin barrier. Repeated skin contact with metallic tools introduces an occupational allergen exposure. However, data on nickel and cobalt release from commonly handled cutting tools remain limited.
Objectives:
To estimate nickel and cobalt spot-test positivity in hairdressing tools used in Danish hair salons.
Materials And Methods:
In this cross-sectional field study, 58 voluntarily participating Danish salons were visited from 1 March to 30 June 2026. Scissors, hair clippers and razors were each tested once for nickel with dimethylglyoxime and for cobalt with nitroso-R salt colorimetric spot tests.
Results:
Among 266 tools (167 scissors, 95 hair clippers and 4 razors), 37 (13.9%) were positive to nickel and 18 (6.8%) to cobalt. Nickel positivity was 15.6% in scissors and 10.5% in hair clippers; cobalt positivity was 6.6% and 6.3%, respectively. At least one positive tool occurred in 22/58 (37.9%) salons for nickel and 12/58 (20.7%) for cobalt.
Conclusions:
Nickel and cobalt release from commonly used hairdressing tools is a prevalent occupational hazard. These findings underscore the necessity of proactive preventive strategies, such as careful material selection and stricter regulatory oversight.
