Rapid onset vancomycin-induced thrombocytopenia confirmed by vancomycin antibody test

We report a case of vancomycin-induced thrombocytopenia (VIT) with rapid onset after re-exposure to vancomycin. A 58-year-old man with cellulitis was initiated on vancomycin. Approximately 1 hour into the vancomycin infusion, the patient developed an infusion-related reaction. Vancomycin infusion was stopped. A complete blood count obtained 4 hours after discontinuation of the vancomycin infusion revealed a platelet count of 31 ×10-⁹/L. Investigations ruled out likely causes of thrombocytopenia. VIT was diagnosed based on clinical symptoms and confirmed with drug-dependent platelet antibody testing. Without complications, platelet counts recovered within 7 days after discontinuation of vancomycin. No correlation between vancomycin level and VIT was observed.