Contrast Dye

Iodine Allergy

The iodine has a great impact on the development and growth of our body. The iodine is extensively available in sea water and soil. The trees in tropical area consume a lot of iodine from the soil which in turn is later eaten up by human and other animals. For adults, 150mg of iodine should be taken every day for the thyroid gland to be working properly. The maximum amount of iodine is stored in the thyroid gland which synthesizes thyroid hormones. Due to lack of iodine, one can be suffering from goiter. Thus it is essential to ingest even a little of iodine every day for the body to keep up some activities inside the body. The iodine allergy is becoming common among people due to increasing usage of Radio Contrast Media (RCM) such as X-rays, CT scans, ultrasound etc. While doing RCM, for a better and sharp picture, a trace of iodine is ingested to the vein. This results a sharp picture of liver, kidney, lung, brain etc. Around 10 million times RCM are being used in the USA for radiological studies which are increasing regularly. In prior to such tests, patients are often asked whether they are allergic to iodine or shellfish. So, what could be the reason behind this?

Cross Sensitivity between the Iodine and Shellfish Allergy:

There is a misconception among normal people is that those who are allergic to shellfish might suffer from iodine allergy too. They assume, because shellfish are grown up on the sea which is rich in iodine, so there is a cross sensitivity between iodine and shellfish allergy. But this is very important to understand that both are different types of allergy. Shellfish allergy causes due to the protein that sea fish has in it and this is blocked by the immune system of the body. Even you might not be allergic to a particular family of shellfish just because you are allergic to another family. The mollusks include squid, octopus, cuttlefish, oysters, limpets etc and crustaceans include prawn, shrimp, lobster etc. They are two different families and consist of different type proteins. You might be allergic to both family and either one of them. So, when someone says he has an iodine allergy this means it is due to iodine-based contrast dye and not because of the protein in shellfish. Having said that it is to remember that radiologists found only a few percent (around 3%) of shellfish allergic have the possibility of iodine allergies. Usually the symptoms are mild such as vomiting, nausea, skin hives etc. But iodine allergy symptoms can be severe with an anaphylactic attack which shows some major health issues such as breathing difficulties, low blood pressure, unconsciousness etc. Those who are already allergic to Radio Contrast Media carry high risks of iodine allergies for sure.

Iodine Allergy Symptoms:

The allergy to iodine can be anticipated with the symptoms mentioned below. But this is very important to perform tests under the observation of the doctor to ensure about it.

  • Abnormal heart rhythms
  • Asthma
  • Anaphylactic (in rare cases and higher allergic reaction)
  • Cardiac arrest
  • Convulsions
  • Difficulty breathing
  • Flushing
  • Headache
  • High or low blood pressure
  • Itching
  • Mild skin rash or hives
  • Nausea
  • Severe skin rash or hives
  • Shortness of breath or difficulty breathing
  • Swelling of the throat or other parts of the body
  • Vomiting
  • Wheezing

Should I go for Medical Tests?

If you want to ensure about the appropriate type of allergy that you are suffering from then undergo for medical tests. There are quite a few tests available to detect the iodine allergy such as scratch, patch and intradermal etc. The allergists will decide which form of test will accurately detect it. The scratch test requires to apply a trace of iodine underneath the skin of the patient and observe the response of the skin surface. For intradermal test, allergen concentration is inserted in the upper layer of the skin with the help of injection. A blood test might be required in order to confirm about the particular food allergy.

Treatments to Curtail Hypersensitivity Reaction:

To treat, it is necessary to consult with the doctor who can suggest you exactly how to approach for the treatment. While preparing for RCM, you are suggested to take medicines in prior to the test. You can ask for pre-medications such as Steroids or Benadryl to reduce the chances of severe allergic reactions or anaphylactic shock which is life threatening. Also discuss the matter whether there is any alternative way to do RCM and the amount of risks is involved in it. When you don’t have any option to avoid imaging tests, then this is better to consume medicine first in order to prevent the danger of iodine allergy. In case of anaphylaxis, this is better to ask help from a doctor. This the most severe reaction and it only happens when the severity of the reaction is at its pick. A close observation of the doctor is also necessary.