What should I be looking for an allergic reaction to the contrast medium?

Contrast medium. These include a feeling of warmth or flushing, a metallic taste in the mouth, light headedness, nausea, itching and hives. Usually, these symptoms are mild and disappear quickly. However, it is a good idea to tell the radiologic technologist if you experience any of them. In extremely rare instances, these side effects can be serious. The technologist will monitor you carefully for signs of side e.