Contrast induced allergic reaction
- Approximately 75 million doses of iodinated contrast agents are given worldwide each year
- Many patients will report allergies to shellfish, iodine, or prior contrast infusions
- Prior allergic or anaphylactic reaction to contrast infusion (whether low osmolality or high osmolality) is a contraindication to future contrast administration
- Asthma (most common)
- Beta blocker use
- Clinical diagnosis
- Patients often report various allergies and there is controversy over the best way to prevent possible contrast induced allergic reaction
- This allergy is specific to shellfish and does not cross react due to the Iodine rich nature of fish and the fish's tropomyosins and parvalbumin
- No pretreatment is necessary for shellfish allergies
- There is no Iodine allergies which are compatible with life due to the existence of iodine in human thyroid tissue and distribution throughout the body
Prior Contrast Allergies
- Pretreatment should not be attempted in these patients since there is a strong association between a prior contrast reaction and future anaphylactic contrast reactions
Pretreatment with Steroids
- Any contrast reaction that is mild such as pruritus or mild urticaria can be observed in the emergency room for recurrent reactions
- Severe anaphylactic reactions requiring multiple administrations of epinephrine should be admitted.
- Patients receiving a single dose of epinephrine should have clinical judgment applied as to observation or discharge
- All patients should be prescribed an Epinephrine Auto Injector regardless of disposition
- Schabelman E, Witting M. The relationship of radiocontrast, iodine, and seafood allergies: a medical myth exposed. J Emerg Med. 2010 Nov;39(5):701-7.
- Lasser EC et al. Pretreatment with corticosteroids to pre- vent adverse reactions to nonionic contrast media. AJR AM J Roentgenol. 1994 Mar;162(3):523-6.
- Wolf GL et al. Comparison of the rates of adverse drug re- actions. Ionic contrast agents, ionic agents combined with steroids, and nonionic agents. Invest Radiol. 1991 May; 26(5):404-10