Allergic reaction to the contrast dye for cat scan?

See below: Allergic reaction to ct scan contrast may range from mild skin rash and itching to severe skin rash and cardiac arrest. Patients at risk are those with previous adverse reactions to iodine-based contrast materials, history of asthma, history of allergy. Contrast reaction may be reduced or prevented if appropriately treated before the scan, but this is not 100%.

May need steroids: If your allergy is not severe, the radiologist may prescribe a low-dow corticosteroid like a Medrol (methylprednisolone) dosepak, to take several days prior to a ct scan with contrast. This may suppress or reduce an allergic reaction so you can have the necessary scan.