We present the case of a patient who had experienced a fever of unknown cause for >7 months after surgical treatment for hallux valgus. A patch test revealed a positive reaction to a titanium alloy. All symptoms subsequently disappeared after we removed the implanted titanium screws. Histopathologic examination of the tissue surrounding the screws showed macrophage infiltration in the tissue. For >1 year after removal of the titanium screws, the patient's body temperature remained <37°C. These results support a diagnosis of titanium allergy in our patient. To the best of our knowledge, a long-term fever caused by an allergic reaction to mini-titanium screws of such a small size has not been reported. A review of 16 cases of titanium allergy reported in the published data confirmed that titanium allergy is extremely rare and that the clinical symptoms can vary. Titanium allergy should be suspected when a patient presents with a fever of unknown cause, delayed wound healing, dermatitis, or impaired fracture healing after internal fixation with titanium materials. A patch test for titanium or the lymphocyte transformation test could offer guidance for the clinical diagnosis of titanium allergy. Finally, we recommend that all patients should be asked whether they have a history of an allergy to any metal before surgery.
Level of Clinical Evidence: 4