Abstract: | Background: Hair cosmetics, in particular hair dyes, bleaches, and permanent wave solutions, contain a number of potential contact allergens. The pattern of exposure to these in hairdressers, clients and home‐users may change over time. Patients and Methods: Data on female patients who consulted centers of the Information Network of Departments of Dermatology (IVDK, http://www.ivdk.org ) between 01/2003 and 12/2006 was analyzed. Patients were divided into a) hair‐dressers, given they worked in this occupation and suffered from occupational skin disease (n = 480),and b) “clients”,who never worked as hairdressers, but in whom hair cosmetics were considered a potential cause of contact dermatitis (n = 780). Results: In hairdressers, the most important allergens were ammonium persulfate (21.7% positive),p‐toluenediamine (PTD,19.6% positive),p‐phenylenedi‐amine (PPD,18.1% positive) and, with decreasing time trend, glyceryl monothioglycolate (2005/2006 still 7.5% positive). Biocides must be regarded as important allergens in hairdressers, namely,(chloro) methylisothiazolinone and methyldibromoglutaronitrile. Clients, who were considerably older on average, had possibly been tested in a more aimed fashion, yielding (strikingly) higher sensitization prevalences to a number of allergens of oxidative hair dyes such as PPD or PTD. Conclusions: The continual analysis of sensitization prevalences in patients patch tested can identify areas needing in‐depth research and preventive intervention, such as avoiding the use of certain biocides in shampoo intended for professional use by hairdressers or further reducing the concentrations in oxidative hair dyes. |