Data on 134 consecutive nickel-sensitive subjects attending our contact dermatitis clinic were analysed. The female to male ratio was 8 to 1, with a mean age at presentation of 35 years for women and 53 years for men. Hand dermatitis occurred in 49% of patients and in 70% of men. It was usually preceeded by jewellery or metal contact dermatitis for some months or years. Although office workers made up the largest occupational group, cleaners, housewives, catering staff, nurses and hairdressers were represented among the women. Several of the men had had heavy occupational exposure to nickel. Cobalt co-sensitivity occurred in 29% of subjects. Sensitivity to 3 or more allergens was found in 32% of those studied but was seen in 2/3 of the men. The prevalence of a personal history of atopy was not raised. A majority of women had had their ears pierced: in 2/3 the nickel dermatitis followed this procedure but in a third it had occurred before. Female sex, jewellery contact and wetwork occupations all predispose to the development of nickel sensitivity.