Contrast allergies are a common concern for cancer patients, as they often require imaging studies to evaluate their cancer.
CT scan contrast
Contains a small amount of iodide
5 to 10% of patients have mild reactions (feeling of warmth, nausea/vomiting)
1% of patients have severe symptoms including rash, hives, swelling, severe nausea and vomiting
Reactions are histamine mediated, but not true "allergic" reactions
Life threatening reaction are rare.
Patients with seafood and shellfish allergies are not at increased risk. These patients have allergies to proteins in seafood and shellfish, not iodine.
Patients with allergies to topical iodine cleaners (betadine) are not at increased risk.
Risk Factors for CT Contrast Allergy: Patient with history of asthma, allergies, heart disease, kidney disease, females, elderly, and patients taking Beta blockers.
MRI contrast/ Gadolinium
Not related to CT contrast dye
Reactions are rare
Rare cases of nephrogenic systemic fibrosis/nephrogenic fibrosing dermopathy reported in patients with renal failure receiving gadolinium. This manifests as stiffness of the skin and may affect movement at the joints. The risk of this rare complication increases with a creatinine clearance of less than 30 ml/min.
PET scan/ FDG (fluorodeoxyglucose)
Not related to CT contrast dye, this is radiolabeled glucose and usually well tolerated
Reactions are rare, but reported
Kidney injury not a concern
Premedications for Patients at High Risk for Contrast Reactions