Allergic contact sensitization in an unselected Danish population. The Glostrup Allergy Study, Denmark

The distribution of allergic contact sensitization was assessed in an unselected population, living in western Copenhagen, Denmark. Ready-to-apply patch tests comprising 23 haptens and mixtures of haptens were mailed to 793 adults, and 567 (71.5%) participated. The tests were read 2 days after application. A total of 111 positive reactions were found among 86 (15.2%) subjects. Sensitization was less frequent in men than in women (11.5% versus 18.8%). Twenty out of the 23 chemicals in the test elicited positive reactions. Positive reactions to nickel and thiomersal were found most frequently (6.7% and 3.4%, respectively). Concerning the other chemicals the frequencies were 1.1% or less. Nickel sensitivity was less frequent in men than in women (2.2% versus 11.1%). The frequencies of sensitization probably represent minimum figures. Regulation of exposure needs to be considered in order to prevent primary sensitization and disease recurrences in those already sensitized.