Allergy and Immunology
Reactions to intravenous contrast media are characterized by direct histamine release, not
IgE mediated.  

In addition, there are currently no proven preventive medications for intravenous contrast
reaction, although diphenhydramine and glucocorticoids are occasionally used.

Also called anaphylactoid reaction in past. Nonimmunologic, or direct, triggers also include
exercise and cold.
Contrast Allergy