Titanium Allergy: A Retrospective Review of 166 Patch Tested Patients

Although most patients do not develop hypersensitivity reactions to metals in implanted devices, when they do occur, significant morbidity can result. Titanium-based systems are often considered as an alternative option in metal-allergic patients; however, there are few studies published on titanium allergy and allergic reactions to titanium in implants may be overlooked in clinical practice. Our aim was to further characterize a single institution's experience with titanium patch testing and evaluation of titanium allergy. We performed a retrospective medical record review of 166 patients evaluated for titanium contact allergy between January 2018-August 2023. Of the 166 patients in our cohort, 67 were referred for pre-implant patch testing and 64 for post-implant patch testing; 35 were tested for reasons unrelated to an implant. Twenty-six of the 166 patients were PTP to titanium (15.7% positive rate). Titanium PTP rates were higher for post-implant cases (28.1%, 18/64) compared to pre-implant cases (6.0%, 4/67) (χ² 9.97, p = 0.002). Among 18 titanium PTPs identified for the 64 post-implant cases, 8 were likely relevant, 8 possibly relevant, and 2 not likely relevant. Further studies should be performed to evaluate the incidence of allergy to titanium implants and to continue surveillance of changes in sensitization rates.