The frequency of contact sensitivity in North America 1972-74.

Three thousand subjects in North America were patch-tested with 19 allergens. The most frequent sensitizers observed include nickel sulfate, caine mixture, potassium dichromate, balsam of Peru, thimerosal, ethylenediamine hydrochloride, paraphenylenediamine and thiram. The prevalence data compared with an earlier study indicates that the initial allergens reported warrant their continued inclusion in a routine patch test screening series in North America.