Long-term follow-up of vasculitis with metal allergy after cerebrovascular coil embolization

Interventional treatment using catheters, particularly coil embolization, is a common therapy for cerebral aneurysms. While generally safe, complications such as allergic vasculitis due to metal allergies can occur. We report the case of a 57-year-old Japanese woman who developed vasculitis after undergoing coil embolization for a cerebral aneurysm. Two days post-procedure, she presented with left-sided facial paralysis, paresis, and hearing loss. MRI revealed multiple small lesions, and vasculitis due to metal allergy was suspected. Treatment with steroids led to improvement, and steroid therapy was tapered off within a year. Allergy tests performed post-treatment identified a positive reaction to the GDC coil and potassium dichromate but not to nickel or platinum. Unfortunately, recurrent vasculitis lesions were detected following the patch test. This case highlights the importance of considering metal allergies before coil embolization and the potential risks of allergy testing after the procedure.