Patch testing with hexavalent chromium salts in different vehicles and with nickel and cobalt in petrolatum

In approaching the question as to which test preparations are most suitable for patch testing of metals, 25 chromium sensitive patients were tested with 0.5% potassium dichromate either in water or petrolatum. The aqueous solution proved better than the petrolatum preparation at a 48 h reading with Neodermtest Roc. No difference in sensitivity was recorded between 4 hexavalent chromium salts. 3 patients who were only sensitive to chromium solution in water also reacted positively to a 1% cobalt chloride solution and a 5% nickel sulfate solution in petrolatum.