Variation and covariation in patch test reactivity to palladium and nickel salts
Concomitant reactions to palladium chloride (PdCl2), sodium tetrachloropalladate (Na2PdCl4), and nickel hexahydrate sulphate (NiSO4·6H2O) are very common during patch testing and have mainly been explained by cross-sensitisation. Whether there is variation in reactivity to palladium or covariation to nickel and palladium is not known. The aim of this study was to investigate the variation in patch