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Preventing Contrast Allergies: Education, Protocols & Premedication

Author Gabrielle Gard covers Preventing Contrast Allergies: Education, Protocols & Premedication on BackTable VI

Gabrielle Gard • May 6, 2022 • 90 hits

While “iodine allergy” has long been a part of the medical vocabulary, Radiologist Dr. Cullen Ruff encourages healthcare providers and patients to omit this from their vocabulary and instead name the specific contrast allergy. Because of the "iodine allergy" misnomer, only 1.6% of patients with contrast allergies know the name of the contrast agent that is actually responsible for their allergy, which is significantly lower than the 60-70% of patients who know their drug allergies.

The BackTable Brief

• Healthcare providers play an integral role in clarifying common misconceptions about “iodine allergies” as well as in changing documentation protocols to include specific contrast agents and timeframes of allergic reactions.

• Currently, only about 1.6% of patients know what contrast agent they are allergic to, and these patients only know because their providers emphasize this information in their visits.

• While current practices place a large emphasis on steroid premedication, Dr. Ruff suggests that the most effective protocol for patients, especially severe allergic cases, is to change the contrast agent itself.

• Dr. Ruff mentions that steroid premedication can better patient outcomes as an addition to changing the contrast agent, but without changing the contrast agent, the premedication will delay patient intervention and increase healthcare costs.

Iodine contrast allergy filter placement with contrast

Image provided by Dr. Aaron Fritts.

Table of Contents

(1) Documenting Specific Contrast Agents

(2) Detecting Contrast Allergies With Smarter Intake Protocols

(3) Contrast Allergy Premedication: Are Steroids Sufficient?

Documenting Specific Contrast Agents

As many patients may not know the details of their contrast allergies, Dr. Ruff urges all healthcare providers to take the extra time to clarify the exact contrast agent and the timeline of the allergic reaction. Dr. Ruff suggests that providers can use certain clues to clarify medical records, such as before 1985, patients would have received an old ionic agent. It is also imperative for providers to figure out if the “iodine allergy” is describing common misconceptions, such as Betadine soap or shellfish, rather than intravenous contrast allergies. Changing the documentation for contrast allergies on a wide scale is no easy task, but Dr. Ruff suggests that educating both providers and patients is the key for better patient outcomes.

[Dr. Christopher Beck]:
Clearly we've mentioned that we need to be documenting the exact agent that's being used. So no longer contrast allergy, certainly not iodine allergy, but contrast allergy and specifically allergic reaction to ISOVUE. And then after that also would recommend like the techs, nursing, and the radiology staff would recommend or would document the type of reaction severity. What else?

[Dr. Cullen Ruff]:
Well, those are the most important things. So again, knowing what the patient had and reacted to so that you can use something different, understanding the severity of the reaction. If the patient's allergy was remote and they don't remember when or where it occurred, then you have to do the best you can. So again, if you know, it was before 1985, it was basically certainly an old ionic agent. If it was somewhere between that period and the early two thousands, you may have to dig because a lot of people were still getting older ionic agents. And you have to try to do the best you can with regard to old record obtaining. The patients, I can tell you, the patients are usually not going to know as well as we'll discuss with my own study, but it's one of these changes we all have to make in order to make it better next year, even though it may be a little cumbersome right now.

[Dr. Christopher Beck]:
Right. So there's some backup work that we have to do with existing allergies. So there's a little bit of unwinding that we really have to do in terms of patients who come to the radiology departments and say, “I have an iodine allergy,” right?

[Dr. Cullen Ruff]:
That's right. But there are things we can do to make the situation clear and more efficient for everyone. You first do need to tease out what do they mean by that because again, that can mean at least three different things, depending on whom you ask. So that may mean a contrast allergy, it may mean a Betadine or an iodine soap allergy, or it may mean shellfish allergy. So first you try to distinguish what the people are talking about. When you can remove the food allergies and the topical soap allergies, then you just focus on the intravenous contrast allergies, and if you can't whittle it down any better, you can at least say, rather than saying that someone's allergic to iodine, at least specify that it was some unknown iodinated contrast agent. If you know it was before the mid eighties, then you can even add further that it had to be an old ionic agent, but you do the best you can.

[Dr. Christopher Beck]:
And I think that's one of the things that we had pushed back with our techs, we thought about taking out iodine allergy from the Epic dropdown list. And not that the techs were opposed to that, but their argument was that they now understood that you can't have an iodine allergy, but a lot of these patients, who were uninformed were using iodine allergy as a way of talking about that they had a reaction to CT contrast dye, and so I think that it is just the labor or the work of going through and spending time with the patients to really tease apart what exactly they had a reaction to.

[Dr. Cullen Ruff]:
Well, but there are things that we could all do that would be a little more efficient. First of all, some of these changes or implementations we're making in my practice, this fall based on our own paper and some of these other studies. We want to have all this information available on our website. We want to make it available to patients when they're scheduling ACT procedure or a vascular interventional procedure. And we are planning on mailing out something to all of our referring docs, explaining the differences. Let me just give you a scenario, something that actually happened. We had a case in going through all the data, I found at least one case where the technologists called the covering radiologist and said, “The patient has never had contrast, but had an anaphylactoid reaction to shellfish.” The radiologist made the decision, which was unfortunate of saying, “Well, go ahead and withhold the contrast just to be safe.” Well, that patient was now had their contrast withheld. When they came to us, that patient will probably never consent to getting IV contrast unless they have a whole lot more education because this radiology practice withheld it. But it's not just that one patient, their doctor now knows that we withheld contrast on someone with a shellfish allergy, and therefore the doctor may never order a contrast study again on anybody with a shellfish allergy. So you have to look at the broader picture here. The changes have to occur in order to get the right patients, to having the right study, and to not have these delays in care, which include delaying the study because people may be getting unnecessary steroid premedication, which takes hours.

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Debunking Contrast Allergies with Dr. Cullen Ruff on the BackTable VI Podcast)
Ep 168 Debunking Contrast Allergies with Dr. Cullen Ruff
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Detecting Contrast Allergies With Smarter Intake Protocols

While provider and patient education reduces common misconceptions about contrast allergies, inquiring in patient questionnaires about intravenous iodine-base contrast allergies rather than generic iodine allergies streamlines patient prep for CT scans in Dr. Ruff’s practice. That said, Dr. Ruff’s research has found that only about 1.6% of patients who have a contrast allergy know what contrast agent they are allergic to, which is significantly lower than the approximate 60-70% of patients who know their drug allergies. This 1.6% of patients knew the specific contrast agent because their provider made the point of relaying this information to them. This is the shift in practice that Dr. Ruff is advocating for, as a more widespread appreciation for specific contrast allergies will help to reduce unexpected allergic complications.

[Dr. Christopher Beck]:
What are some things that people can implement in their practice that can help unwind this that are some low hanging fruit?

[Dr. Cullen Ruff]:
Well, one thing that we already did several years ago has worked out very well. And that was to change our patient questionnaire. When I came to the practice and for, well over a decade into it, the old patient questionnaire that someone else wrote out, asked the question: are you allergic to iodine? And once I started doing the research on this issue and realized that that term was nonsensical and confusing the issue and not good for patient care, I changed the questionnaire with the approval of the practice. So we changed that term from are you allergic to iodine to are you allergic to iodine-based contrast? And what we found was there was no increase in allergic reactions in the offices. So nothing bad happened from it, but I then did a study that I haven't published in print, but I did present at the ACR Annual Meeting of Quality and Safety last fall. And we found that the technologists had the opinion that changing that questionnaire, just the terminology wording, made their patient prep for CT studies more streamlined and faster because by asking a more targeted and accurate question, are you allergic to intravenous iodine-based contrast, it was clear for the patients to answer, and we don't ask any more about shellfish or other non-related allergies.

[Dr. Christopher Beck]:
So, Cullen, another thing I wanted to ask you now, along the vein of research, can you give the audience the crux or the bullet points to the paper that you recently published?

[Dr. Cullen Ruff]:
Absolutely. I'd be honored to. So because the subject has become such a clinical interest of mine, we did our own study because again, you asked why is it that we're going to have trouble making the changes that we need in terms of labeling contrast allergies by name. And it's always been my unquantified perception that patients know very little about their own contrast allergies and much less than they know about other medication allergies in general. And so that was what we looked at. We did a keyword search within our database and came up with a cohort of over 300 patients who have a confirmed contrast allergy, and we ask them some simple questions. The patients were very good at being able to describe their symptoms. So 87% of the patients with a prior allergy could describe the symptoms. And we removed the people who described symptoms, just like flushing, nausea, and vomiting. We didn't count those because we knew that those are just physiologic, but out of people who had more of a confident contrast allergy, the patients were great at knowing their symptoms equal to other studies that are in pharmacology literature. But we asked the patients, “When did your allergy occur?” Because that's important to know. If they know when their allergy occurred, that helps us determine if it was one of the older agents or one of the new. Only 37% could estimate the year when they had their reaction, and an additional 7% said a long time ago, and about 57% just could not estimate when it had happened. Then we asked them, “Where did your reaction occur?” And we would take either the city and state or the name of the hospital or clinic, just to be inclusive. But only about 40% of the people could tell us where, and 60 could not. And so that obviously tells you, you're not going to be able to get the old records the majority of the time. If these people can't tell you, and again, our study was done on outpatients and a private practice, most of whom are coming in walkie talkies. They either speak English or they have someone with them who does. So it would be even worse if you were talking about people coming into a hospital emergency room who are more acutely ill and less able to answer these questions. Then came the main question, which was can you tell us the name of your contrast allergy. Now, other studies in pharmacology literature have estimated that before counseling with a pharmacist, patients are about 60 to 70% accurate in being able to name their drug allergies. And after counseling with the pharmacist, patients are maybe 80 to 95% accurate in terms of knowing their own allergies. But when we asked patients, can you name your contrast allergy? Would you care to guess what percentage could?

[Dr. Christopher Beck]:

[Dr. Cullen Ruff]: of patients who have a contrast allergy, were able to say which one it was, and we've just got to do better than that because if patients don't know, then we're not going to be able to give them something different. Because there were so few, five out of 307 patients, who knew what they were allergic to, I even called them.

[Dr. Christopher Beck]:
You called the five patients?

[Dr. Cullen Ruff]:
It was a short list. So I called them, and I said, “Why is it that you knew when most people did not?” And the answer that I got repeatedly was when I had my reaction, the technologist or the radiology, told me what I had been injected with, and they gave it to me in writing.

[Dr. Christopher Beck]:

[Dr. Cullen Ruff]:
So you asked what are changes people can do. That's one of the things we're going to do every time we get a patient back into our practice, who's had a reaction, whether it's a new one today or a previous one, our goal is to print out for the people, what they reacted to. We want them to list this on all of their medical records by name and that way we'll know what we can avoid in the future and give them something different.

[Dr. Christopher Beck]:
Have you guys worked with your EMR of choice, whether it's Epic or Cerner, to add the names of the contrast agents, like the specific contrast agents to help with documenting contrast allergies?

[Dr. Cullen Ruff]:
The specific contrast agents are choices within the electronic medical records. We also use Epic. And if you want to type in that someone has an allergy to Omnipaque, ISOVUE, Optiray, Visipaque, or whatever, you can do that, it's just that most people haven't narrowed that down. So the choices are there. The work that we need to do is to work with Epic or whichever EMR system to have them not offer iodine as a choice because, as we've discussed, that's a nonsensical term that we don't want to encourage people to use. And we want people to be more selective and specific. So if that is a previously existing allergy, maybe there could be some dropdown choices to narrow it down, whether it's a contrast agent or something unrelated like topical iodine soap or shellfish or something else.

[Dr. Christopher Beck]:
That's great work that y'all are doing. How long have you guys been documenting the exact contrast agent in the EMR?

[Dr. Cullen Ruff]:
Oh, when I say, we, this is not consistent at all. So it's something that I've started doing because of the research we've been doing, but the more, comprehensive approach is something we're just starting in the outpatient practice. And it's going to take more time and more effort at the hospital because there are so many more people who use the system.

[Dr. Christopher Beck]:
Of course. Yes, sometimes it's as much about education and outreach. There's only so much one person can do, so good luck fighting the good fight.

[Dr. Cullen Ruff]:
Well, thank you. It's going to be an uphill challenge, but it's in the patient's best interest and it's in our best interest too because it makes the workflow more efficient for the technologists and the radiologists, where every time a patient may have an allergy, and everything comes to a grinding halt because you have to answer these questions for the umpteenth time. I think if people realize we're doing ourselves a favor by being accurate, then I'm hoping that the pattern will pick up.

Contrast Allergy Premedication: Are Steroids Sufficient?

Dr. Ruff explains that steroid premedication has shown little to no benefit in patients with very severe allergic reactions. Even though steroid premedication is fairly low risk, Dr. Beck and Dr. Ruff agree that without changing the contrast agent the patient is allergic to, premedication will only delay patient intervention and increase healthcare costs, which is not optimal. Dr. Ruff concludes that instead of relying on contrast allergy premedication, using a different contrast agent is more effective to avoid future allergic reactions. Dr. Ruff also refers to studies that have demonstrated that changing the contrast agent and providing steroid premedication together may be the most effective protocol.

[Dr. Christopher Beck]:
So if we think iodine allergy should be removed, what should we be telling patients when they have an allergic reaction? So we'll go back to a scenario where a patient has an allergic reaction to a non-ionic or a recent contrast allergy, like during a CTA or whatever. What should we be telling that patient? Or what should we, as the physicians or some of the technologist, what should we be documenting?

[Dr. Cullen Ruff]:
The first thing you document is the actual contrast agent given by name, just like you would any antihypertensive or any antibiotic or any other drug that a patient has an allergic reaction to because what's most important is the next time this person needs a contrast injection, you can give them something different. We'll use penicillin G as the rogue antibiotic example here, if someone's allergic to penicillin G, and they need an antibiotic, what makes more sense to you: to give them the antibiotic that they're allergic to plus steroids to premedicate or does it simply make more sense to give them a different antibiotic that they've never had? And that's what we're going to discuss here. That's the same thing when it comes to contrast, we have to know by name what people have reacted to so that we can give them something different because giving people a different agent is the best way to prevent a future reaction much more so than steroid premedication.

[Dr. Christopher Beck]:
Another scenario, so if a patient has an allergic reaction and I'm going to use trade names as well, like Omnipaque 350, then if that patient comes back, having had a documented allergic reaction, you would recommend as the radiologists that, “Hey, let's try something different, like ISOVUE or Visipaque.” Is that right?

[Dr. Cullen Ruff]:
Absolutely. So ISOVUE, Visipaque, Optiray, Omnipaque, those are some of the most commonly used current low osmolar and lower allergenic agents. And yes, you would simply choose a different one.

[Dr. Christopher Beck]:
And if you had that patient to see, like say you knew that they were coming in ahead of time, what about the premedication protocols?

[Dr. Cullen Ruff]:
I think it depends on the severity of the reaction. Although I will say the latest studies that have come out have actually shown very little to nearly no benefit with steroid premedication in the patients who have had the most severe reactions. So there've been some other studies that have said, and I think this all depends on the study design: there's always going to be some inherent differences in terms of who's included, who's excluded how the data is looked at. There have been other studies that have shown that a steroid premedication in addition to changing the contrast agent given, is even more effective than changing the agent, but changing the agent is the most important component, more so than the steroid premedication.

[Dr. Christopher Beck]:
Right. And it's fair to say that, I know that my practice mirrors this, we put a huge emphasis on the steroid premedication protocol, and we rarely talk about changing the agent, but that's why I was so interested in having you on because that really needs to be the discourse about changing the agent, focusing on what they had an allergic reaction to, and then using something slightly different.

[Dr. Cullen Ruff]:
That's right. And what we'll talk about on our show here is the fact that it's hard to know what the patient was allergic to because the focus of our study was to see just how little the patients with a contrast allergy know about their own allergy. And unfortunately their knowledge is quite limited and there is a large opportunity for us to not only educate ourselves, the radiologists and the technologists, but definitely the patients and their referring, ordering doctors.

[Dr. Christopher Beck]:
Actually one of the things that I think that the ACR manual references is that the premedication protocols in and of themselves are fairly low risk. And I think that's one of the reasons they continue to persevere is that, oh, what's the downside, right? You're talking about three doses, maybe two doses of steroids about half a day before you receive your contrasted study. But I think like the real downside with the premedication protocols is that there can be a delay in patient care and added cost to the patient. It's one more barrier to entry that can already be kind of a daunting process for just like the layperson.

[Dr. Cullen Ruff]:
All of that is true, but the other downside is the premedication does not work.

[Dr. Christopher Beck]:
Oh, yeah, I guess I should've mentioned that, but you did mention that there’s no real good evidence that it works and certainly no good evidence that it works for the people who are at the higher risk for having a bad reaction.

[Dr. Cullen Ruff]:
That’s right.

Podcast Contributors

Dr. Cullen Ruff discusses Debunking Contrast Allergies on the BackTable 168 Podcast

Dr. Cullen Ruff

Dr. Cullen Ruff is a practicing diagnostic radiologist and associate professor in Virginia.

Dr. Christopher Beck discusses Debunking Contrast Allergies on the BackTable 168 Podcast

Dr. Christopher Beck

Dr. Chris Beck is a practicing interventional radiologist with Regional Radiology Group in New Orleans.

Cite This Podcast

BackTable, LLC (Producer). (2021, November 26). Ep. 168 – Debunking Contrast Allergies [Audio podcast]. Retrieved from

Disclaimer: The Materials available on are for informational and educational purposes only and are not a substitute for the professional judgment of a healthcare professional in diagnosing and treating patients. The opinions expressed by participants of the BackTable Podcast belong solely to the participants, and do not necessarily reflect the views of BackTable.



Debunking Contrast Allergies with Dr. Cullen Ruff on the BackTable VI Podcast)



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