Table 3: Categories of Acute Reactions
The following describes a classification system for acute adverse reactions to iodinated and gadoliniumcontaining
contrast media. Acute adverse reactions can be either allergic-like or physiologic. Allergic-like
reactions have clinical manifestations similar to allergic reactions. They are termed “allergic-like” rather
than just “allergic” because they are often idiosyncratic and may differ immunologically from true allergies
despite their similar clinical presentations. A history of prior allergic-like reaction may be an indication
for corticosteroid premedication prior to future contrast-enhanced studies that utilize a similar contrast
material. Physiologic reactions are not allergic-like and represent a physiologic response to the contrast
material. A history of a prior physiologic reaction is not an indication for corticosteroid premedication.
Assessment of reaction severity is somewhat subjective, and it is difficult to succinctly describe all
possible degrees of reaction severity. Sound clinical judgment should be used to determine when and how
aggressively an acute reaction should be treated. However, many mild reactions resolve during a period of
observation without treatment.
Acute contrast reaction management, and delayed allergic-like and non-allergic (e.g., CIN, NSF) adverse
events to contrast media, are described elsewhere in this Manual.