Cytokine Release Syndrome-like Reactions Following Exposure to Iodinated Contrast Media: A Case Series

Hypersensitivity reactions to iodinated contrast media (ICM) are traditionally categorized as immediate or delayed reactions, involving IgE-mediated pathways, non–IgE-dependent mast cell or complement activation, or T cell–mediated immune mechanisms. However, we observed that some individuals develop systemic inflammatory responses that do not fit these established categories. We describe here a case series of three patients who developed cytokine release syndrome (CRS)-like reactions following iodinated contrast administration, which were initially difficult to distinguish from sepsis and were only recognized after recurrent episodes. Clinical presentation, laboratory findings, cytokine profiles, allergy investigations, and treatment outcomes were reviewed. All patients developed fever, rigors, and hypotension within 5 to 70 h after exposure, accompanied by leukocytosis and markedly elevated inflammatory markers despite negative microbiological investigations. Serum tryptase levels remained within the normal range with no significant rise, while cytokine analyses demonstrated elevations of pro-inflammatory interleukin-6 and other cytokines in patients 1 and 3 where samples were available. Standard corticosteroid premedication did not prevent recurrence, and one patient developed systemic symptoms following intradermal testing. All patients improved with high-dose systemic corticosteroids and supportive care. These findings suggest that ICM may induce a cytokine-mediated inflammatory phenotype distinct from classical hypersensitivity reactions, highlighting the importance of early clinical recognition to guide diagnosis and management.