Platinum group elements in the environment and their health risk.
1307 consecutive patients were patch tested with PdCl2 1% pet. 32 patients were positive; 29 also showed a reaction to NiSO4. 470 patients were additionally tested with a metallic palladium disc. 3 had a positive reaction, and none of them reacted to PdCl2 or NiSO4 pet. A positive patch test to PdCl2 pet. is in most cases probably due to a cross-reaction with nickel in nickel-sensitive subjects. Patients positive to PdCl2 tolerate skin contact with metallic palladium.