BACKGROUND: Nickel and cobalt were not regarded as pertinent contact allergens in the hairdressing trade for the last decades. It was even stated that the relevance of nickel allergy in the hairdressing trade has been overestimated for several years. Recently, nickel and cobalt release from a multitude of metal tools in the German hairdressing trade was documented in two field studies.
METHODS: Review of two field studies.
RESULTS: In 2019, nickel release from 9.2% of 229 tested metallic hairdressing tools was evidenced, and in 2021, nickel release from 27.6% as well as cobalt release from 2.1% of 475 tested tools was detected in overall 30 North German hairdressing salons. Tweezers, sectioning clips, hair clips, and straight razors were identified as nickel as well as cobalt releasing tools. Crochet hooks and tail combs were identified as only nickel releasing tools.
CONCLUSIONS: A variety of metallic tools - which are used daily by hairdressers - release nickel and/or cobalt in allergologically relevant amounts. This circumstance has to be considered problematic with regard to the development of work-related allergic contact dermatitis. Thus, nickel and cobalt should possibly receive greater attention as potential contact allergens in the hairdressing trade.
CONCLUSIONS: The proven nickel and cobalt release from metallic hairdressing tools might entail legal ramifications in terms of insurance law. In case of nickel and cobalt allergies within the occupational group of hairdressers, metal tools might be considered as feasible sources for nickel and cobalt exposure.

Tinea capitis is a dermatophyte infection of scalp is commonly spread by currently infected patients, asymptomatic carriers or by fomites, such as hairdressing tools. However, studies on the risk factors of Tinea capitis remain scarce. The aim of this study was to evaluate the dermatophytes contamination level of the hairdressing tools to which hairdressing salon customers are exposed in Sirakoro-Méguétana, a suburb of Bamako, the capital city of Mali. A total of 41 hairdressing tools were sampled in five hairdressing salons. Two anthropophilic dermatophytes species, Microsporum audouinii (53.3%) and Trichophyton soudanense (46.7%), were cultured from 30 (73.2%) samples. This first study, addressing hairdressing salons dermatophyte contamination, revealed a strikingly high contamination of hairdressing tools with dermatophyte propagules, which exposes hairdressing salons customers to an important dermatophytosis risk. The sterilisation of hairdressing tools is central to preventing dermatophytoses spreading. Appropriate community information and hairdressers training should be implemented in this view.