Q: Is there a connection between shellfish allergies and iodine?
Equating an allergy to shellfish with an allergy to iodine is a fairly common misconception. Fish and radiographic contrast allergies are also erroneously equated with iodine allergies.
Iodine is essential for proper thyroid function. Without it, people become ill with thyroid problems. As it turns out, seafood and crops fertilized with seaweed are a good source of iodine. As people moved from coastal areas inland, the incidence of thyroid deficiency increased. Beginning in the 20th century, it became a common additive in many varieties of table salt. As a result, now you have to work hard to completely avoid it.
The allergen in shellfish is a protein, not iodine. Some people with iodine allergies really have a topical sensitivity to iodine (e.g., povidone iodine; Betadine), usually a much different kind of reaction than the immediate reaction found with anaphylaxis.
Bottom line: A shellfish allergy should almost never preclude the use of iodine for water disinfection. If you are concerned, get more information about the true nature of the allergy. If the person has not had problems with other seafood (saltwater) or table salt, iodine is not the culprit. There are, of course, other reasons for not using iodine as a water disinfectant.
If this a myth then why when I have had surgery and asked if allergic to anything I respond shellfish and they tag me allergic to iodine?
I can’t answer your question as to why the hospital staff would automatically “tag” you as having an iodine allergy based on your history of a shellfish allergy. There is no evidence that an allergic reaction following seafood ingestion is related to the presence or the amount iodine contained.
It is true that people with seafood allergies have a heightened risk for idiosyncratic reactions to the IV contrast used during certain kinds of x-ray studies. Although these materials contain iodine, based on several studies, most believe that the reactions are not due to their iodine component. By the way, there is also a correlation between a heightened susceptibility to IV contrast and many other foods not connected in anyway to iodine or seafood.
Bottom line: As I intimated previously, iodine allergies are rare birds indeed. In your case, I am not sure why it would matter to add iodine to your list based on the shellfish allergy. If there is a concern about IV contrast during your surgical procedure, a shellfish (or any food allergy) should be a heads-up that there is an increased risk of a reaction. If you have any more questions, you might find this link helpful. http://www.radiology.ucsf.edu/patient-care/patient-safety/contrast/iodine-allergy
DJ
During a stay in hospital with pneumonia I was asked if I had a shellfish allergy before being given an MRI. I queried the question and the nurse made it clear he was specifically concerned because he was using an iodine contrast. Now, he didn’t explain the corallation and everyone was cosciensiouse in avoiding giving a straight answer.
Do you not think it possible that, while too few to be of statistical relivense, it’s possible there have been instances of some note? Or that it may be a diagnostic tool for sone other conditions that aren’t allergic but medication based concerns.
I have a severe allergic reaction to shrimp and lobster. I also noticed after scraping my knee and after methilaide was applied, I had a severe rash break-out on the cut. I was told I was allergic to iodine due to both shellfish and methilaide reactions. I was told shellfish had high concentrations of iodine. I can eat salt, dairy products, potatoes, cranberries, and strawberries (all have good sources of iodine) with no problems. Your thoughts?