Metal Hypersensitivity After Cardiovascular Device Implantation Presenting With Refractory Urticaria and Angioedema

BACKGROUND: Systemic hypersensitivity after metallic cardiovascular device implantation is uncommon and may mimic spontaneous urticaria or bradykinin-mediated angioedema. CASE SUMMARY: A 40-year-old woman underwent implantable loop-recorder placement followed 4 days later by percutaneous closure of a secundum atrial septal defect with a 14-mm nitinol occluder. Approximately 5 months later, she developed recurrent generalized pruritic urticaria with facial, lip, and tongue angioedema despite corticosteroids, antihistamines, H2 blockade, montelukast, and epinephrine. Complement component 4 and serial C1-esterase inhibitor testing did not support C1-inhibitor deficiency. Patch testing documented nickel and chromium sensitization. Both implanted devices were surgically removed with primary septal repair. DISCUSSION: The chronology, refractory phenotype, documented metal sensitization, and postexplantation nonrecurrence support an implant-associated hypersensitivity syndrome, although attribution to either device individually is not possible. TAKE-HOME MESSAGE: Consider implanted-metal hypersensitivity in otherwise unexplained refractory urticaria and angioedema after cardiovascular device implantation.