Thanks for writing in. Allergies are common in patient’s after a CAT scan, because of sensitivity to iodine, certain medicines which form the dye. Allergy due to iodine is not the same as the allergy due to shell fish. Because in shell fish there are components like tropomyosin, which have a propensity to cause allergy in certain people and is completely different to what causes allergy due to iodine.
I've been eating shellfish for a long time. I'm from New Orleans, Louisiana. Last year my husband took me to Don's Seafood and I ordered a salad with boiled shrimp, crameat, and crawfish. The next few days I was feeling awful with a terrible headache which I know that happens if I eat too much salt, but I also had about 10 hives. I went to my doctor the next day and he really didn't know the exact prognosis except that I must be allergic to shell fish. What do you think? Of Course, right now everyone is being cautious because of the oil spill. If I have to I will give up shell fish, but does this mean I have to give up taking OMega 3 also?
First, no one is allergic to iodine. It is an atom and you cannot be allergic to an atom. Atoms are too small for the immune system to see. Your NORMAL thyroid gland is full of iodine. You are allergic to the organic molecule to which the iodine is bound, and this molecule is different for topical iodine skin preps vs shrimp vs IV x-ray dye. You can be allergic to any or all of these things, but allergy to x-ray dye is chemically very different from allergy to topical skin preps containing iodine or shell fish.
In general, patients with unrelated allergies are at a 2- to 3-fold increased risk of an allergic-like
contrast reaction, but due to the modest increased risk, restricting contrast medium use or premedication
solely on the basis of unrelated allergies is not recommended. Patients with shellfish or povidone-iodine (e.g., Betadine®) allergies are at no greater risk from iodinated contrast medium than are patients with