Sensitization to palladium in Europe

Area of Science:

• Dermatology
• Allergology
• Contact Dermatitis

Background:

• Sodium tetrachloropalladate (Na2 PdCl4) demonstrates higher sensitivity as a palladium patch test allergen compared to palladium dichloride (PdCl2).
• Understanding palladium sensitization prevalence is crucial for accurate diagnosis and management of allergic contact dermatitis.

Purpose of the Study:

• Determine the optimal patch test concentration for Na2 PdCl4.
• Evaluate and compare the prevalence of palladium sensitization using Na2 PdCl4 and PdCl2.
• Compare palladium sensitization rates with nickel sensitization in a European multicenter study.

Main Methods:

• A multicenter study involving eight European dermatology clinics tested 1651 consecutive patients.
• Patients were patch tested with palladium dichloride (PdCl2) and varying concentrations of sodium tetrachloropalladate (Na2 PdCl4) (2%, 3%, 4%).
• Standard baseline series including nickel sulfate (NiSO4·6H20) 5% pet. were used; age and sex distributions of sensitized patients were analyzed.

Main Results:

• Three percent Na2 PdCl4 pet. was identified as the optimal concentration, with 4% offering no additional diagnostic value.
• Two percent Na2 PdCl4 showed suboptimal reactivity and increased doubtful reactions.
• Palladium sensitization prevalence doubled with Na2 PdCl4, reaching rates comparable to nickel sensitization.
• Unlike nickel sensitization, palladium sensitization was not significantly associated with female sex.

Conclusions:

• The optimal patch test concentration for Na2 PdCl4 is 3% pet.
• Sensitization to palladium is nearly as prevalent as sensitization to nickel.
• Distinct sex distributions between nickel and palladium sensitization suggest differing exposure pathways.