Not only hairdressers, but also their clients or home-users of hair cosmetic products may become sensitized to one of the product constituents. The present analysis addresses the question whether the pattern of sensitization is different in these 2 groups and includes female patients who consulted with the participating centres of the IVDK (http://www.ivdk.org) between 1995 and 2002, and in whom hair cosmetics have been considered as being causative of their contact dermatitis. Among these, 2 subgroups were identified: (i) patients, currently or previously working as hairdressers, diagnosed with occupational skin disease (H, n = 884) and (ii) patients who never worked as hairdressers, i.e. clients (C, n = 1217). Previous atopic eczema was twice as common among H, who were also much younger (median age 24 versus 46 in C). Analysis of sensitization frequencies and patterns showed the well-known decline of contact allergy to glyceryl monothioglycolate (GMTG) in H from 31.2% to 8.5%. Among the C, 1.7% were allergic to GMTG. Concerning p-phenylenediamine, a steady decline from 27.6% to 17.2% was observed in H, while no trend was found in C (12.6% and 16.6% in the first and the last 2-year period, respectively). Conversely, a very slight decline of p-toluenediamine sensitization was observed in H (from 29.5% to 24.8%), while at the same time a significant increase was noted in C (from 8.7% to 16.7%). A slighter increase was also noted with ammonium persulfate in C (3.1-6.8%), while the proportion of H sensitized remained largely constant at about 26%.