Metal Sensitization in Patients That Underwent Patch Test Pre and Post-Implant Exposure.

Background: Sensitization to metals can cause allergic symptoms in subjects that under go device implantation but there is debate on the value of pre-implant patch testing. Objectives: To evaluate metal sensitization in patients that underwent patch test pre and post-implant insertion. Methods: Consecutive patients that underwent patch testing for metals before (n. 665) or after device implantation (n. 217) from January 1998 to December 2022 were investigated. Patch test were performed to investigate sensitization to Al, Au Co, Cr, Cu, Hg, Ni, Pt, Pd, Ti, Va, and Zn. Univariate and multivariable logistic regression were used to investigate factors associated to metals' sensitization. Results: A total of 882 patients were patch tested: 665 without contact dermatitis, that performed the test before device implantation and 217, with symptoms, that did the test after device implantation to verify metals sensitization for the onset of adverse reactions. In both groups, women are more represented (AdjOR 1.80; 95% CI 1.01-3.21 and 2.08; 95% CI 1.03-4.17, respectively). History of jewellery allergy significantly predicted metal sensitization, but only in the pre-implant group (AdjOR 6.11; 95% CI 3.82-9.77). No significant differences in metal sensitization was found in the groups considered. Conclusions: Sensitization to metals were similar in pre-implant and post-implant patients. Women with jewellery allergy are at higher risk to have a patch test positive to metals. Post-implant testing in case of contact dermatitis could be helpful to identify culprit allergens. Pre-implant testing in a selected population with history of contact dermatitis or jewellery allergy could be useful to choose the right implant.