Adult vs. Childhood Food Allergies: A Deep Dive with Dr. Philippe Begin

“I felt I was actually controlling my condition. It wasn't controlling me.” 

                                                                                                                        -- Patient of Dr. Philippe Begin

Join Dr. Mariam Hanna as she sits down with Dr. Philippe Begin, a renowned expert in allergy and immunology from the University of Montreal. They dive into the complexities of adult food allergies, distinguishing them from childhood allergies and discussing both clinical insights and patient experiences.

On this episode:

Understanding Adult Food Allergies: Dr. Begin explains the unique characteristics of adult food allergies, including the differences in allergens and symptoms between adults and children. He sheds light on the under-researched area of adult food allergy practice.

Diagnosis and History: Learn about the critical elements in diagnosing IgE-mediated food allergies in adults. Dr. Begin emphasizes the importance of timing, symptom duration, and consistency in patient history to accurately identify food allergies.

Management Strategies: Dr. Begin shares his approach to managing adult food allergies, highlighting the importance of recognizing patients' experiential knowledge and their tolerance to risk. He discusses the role of food challenges and the careful use of food diaries.

Psychosocial Aspects: Explore the psychological and social dimensions of living with food allergies as an adult. Dr. Begin talks about the varying reactions to food allergies, from fear to confidence, and how past experiences shape these responses.

Empowering Patients: Discover how empowering patients to manage their food allergies can transform their lives. Dr. Begin's stories of patients taking control of their conditions provide valuable insights for both patients and healthcare providers.

Tune in to this episode for a comprehensive look at the evolving field of adult food allergies, offering practical advice and expert perspectives that are essential for anyone dealing with this condition.

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Transcript

Dr. Mariam Hanna:

Hello, I'm Dr. Mariam Hanna, and this is The Allergist, a show that separates myth from medicine, deciphering allergies and understanding the immune system. There was a recent dinner meeting I attended. It was all physicians around the table. The server promptly came to identify any allergies for the evening's meal. Cute, well done, especially if it's an allergy meeting. He politely knelt near this one physician to acknowledge that the kitchen had been made aware of his lactose intolerance and would make any necessary substitutions during our meal for the evening. I didn't even know the physician but heard the entire conversation in this hushed whisper but very serious voice. For some patients, it's actually not an intolerance, and it really does make you wonder how they go about navigating the adult world. We talk about the food allergy epidemic in our pediatric patients all the time, but perhaps the untold epidemic is the one that's coming to the adult world, or perhaps it's already started even now.

Today's guest is going to help us journey through the adult food allergy landscape as it is rapidly evolving. It's my distinct pleasure to introduce Dr. Philippe Begin. Dr. Begin is an associate professor and Quebec Research Fund's senior clinical research scholar in the Department of Medicine, Section of Allergy and Immunology, at the University of Montreal. His research program focuses on the clinical development and evaluation of new interventions in children and adults with food allergy. He has published over 140 peer-reviewed articles on this very topic. He practices at the CHUM and CHU Sainte-Justine in Montreal, where he is the founder and director of the Food Oral Immunotherapy Unit. Dr. Begin, welcome to the podcast.

Dr. Philippe Begin:

Thank you, Mariam. Really happy to be here and to be talking about adult food allergies. We don't talk about it enough, I find.

Dr. Mariam Hanna:

You were actually quite excited when I reached out and said we want to talk. So let's start with the definition. What is adult food allergy actually all about?

Dr. Philippe Begin:

Yeah, adult food allergy, and I'm talking about IgE-mediated allergy, biologically is the same as children's food allergy, but if you look in the literature, you're not going to find much on the topic. So you're probably going to find some epidemiologic papers, which are going to tell you that in adults, there's more male than female, so it's 65% male. In children, it's 65% female. In adults that have food allergy, you're going to find that it's not exactly the same food. So you have adults that had their child onset food allergies, so it's basically the same foods, but then the adult onset food allergy is more going to be related to either your pollen allergies, you're going to have the pollen food syndrome or to your dust mite allergies, you're going to have shellfish allergies. But beyond that, there's not much on the actual practice of adult food allergies. So I guess most of what I'm going to talk about is more personal experience than published hard evidence.

Dr. Mariam Hanna:

Well, this is how evidence has to start anyways. So I accept the challenge and understand the wisdom that you bring along with it. Can we talk about around adolescence or different time periods in a person's life where these types of things can develop or food allergies can develop?

Dr. Philippe Begin:

I don't make a big difference between adolescents and adults after puberty, that's when you start developing your rhinitis. So you could develop it at 10, you could develop it at 25. It's a bit the same with food allergies. It's rarer in the geriatric population, but I've diagnosed an egg allergy at 84. I have no clue how and why that patient developed that, but there's a lot we don't know about how you become allergic in the adult population.

Dr. Mariam Hanna:

Very interesting. Okay, so let's do basics first. What are the elements that we should be looking for in a history in making the diagnosis of an IgE-mediated food allergy?

Dr. Philippe Begin:

So that's a great question because it's usually pretty easy to do in children. So you really need to go back to the history, and I find that the question that's most useful, the first question I ask, is about the timing of onset because oftentimes when you ask it, the patients will tell you, well, you see, the day before I had... I can stop them right now. So with IgE-mediated allergy, the onset is rapid. So usually within 30 minutes up to one hour after that, it's really unlikely unless there's a co-factor that's going to affect the digestion of the rest of the bolus that you would get new onset of symptoms. One exception to that is alpha-gal syndrome, where you would get symptoms 12 hours after eating, but other than that, it's really quick. The other thing that's useful is the duration of symptoms.

So sometimes too, well, they started itching, and it lasted for three days. The allergen is going to remain in your bloodstream for about three to four hours. So if it lasted that long, then it's not a food allergy. So it comes in quickly afterward, and it doesn't last that long. So usually the association is pretty easy to do, and the patient already has a good idea of what he's allergic to. So if he's coming, I think I have food allergies, but I really don't know to what, that lowers the likelihood of it being an allergy. The symptoms that you have are important. So obviously if people are talking about headache or brain fog, those are not symptoms of IgE-mediated allergy, but you need to be careful because it's not because a patient says he had an anaphylaxis or even if there's anaphylaxis written in the chart that that's actually what happened.

So when you ask the story, if they tell you they had rhinitis, they actually had wheezing, that's quite convincing. But if it's only subjective trouble breathing, then it might just be hives but not anaphylaxis. Another thing that can help you is to ask what food it is. Theoretically, any food can give allergies, but some are more frequent than others. So if they're saying it's coffee and chocolate, those are not typical allergens, and they do cause intolerances. You want to look for consistency. So a patient that has a food allergy typically will react every time they're exposed to it. So if they had the food afterward and then it was fine, that kind of rules out allergy. The big exception to that is co-factor dependent food allergy, and what we see in the literature, it's a lot coming from Europe and Japan, they're talking about wheat exercise-dependent allergy.

I really don't see that a lot. What I see a lot is lipid transfer protein, cofactor dependent allergy, so fruit and vegetables. So these patients are mildly allergic to that protein lipid transfer protein in those fruits. And when you do the IgE, it's relatively low, usually around one kilo unit. So oftentimes when you eat the food, it doesn't itch in their mouth and those proteins are a bit thermolabile, but not as much as a PR 10 allergen, which will give you the oral allergy syndrome. So it eventually gets digested and you'll be fine. But if you combine this with a cofactor like alcohol, NSAIDs, exercise, that's when you're going to absorb the allergen and get your anaphylaxis. So when they've already identified the relationship, you don't need to go into this. It's more when it's nebulous what the food is, that's when you want to ask for co-factors. When you have a co-factor, then that food becomes interesting, even if they had eaten it since.

Dr. Mariam Hanna:

I'm scared to ask, do you make them do food diaries around their reactions or how do you get to this?

Dr. Philippe Begin:

Yeah, it depends on the patients. So oftentimes food diaries I find are useful for patients with IBS-like symptoms, which you're not too sure if it's because there was this Nature paper that came out a couple of years ago, which showed that they did endoscopy and they did the equivalent of a skin test in the intestine, and they found that patients had positive testing inside, but the skin test was negative. So I am open to the possibility that it might still be allergy, but the only way that you can test it would then be with a food diary.

Dr. Mariam Hanna:

Okay. Well, I mean food diaries sometimes open this kind of Pandora's box of all these foods are triggers and now we're going to eliminate many foods out of a diet that may not be necessary.

Dr. Philippe Begin:

Yeah. But when you approach it this way, you're at a stage where you say, well, you don't have IgE-mediated allergy, at least not the anaphylactic type. So now you have these IBS-like symptoms and I've already excluded the bad diagnoses because you have your red flags, so the patient doesn't have blood in his stool, anemia, weight loss, he doesn't have symptoms that wake him at night. So that doesn't sound like IBS. But if you don't have any of that, then it might be an intolerance. The food might be contributing to this or it might be IBS. And then the thing is I explain what IBS is because otherwise they think it's in my head. And the idea is what I tell them is there's actually a study that was made, and they would blow up, blow a balloon in the patient's colon, and they realized that patients with IBS would feel the balloon when it's reached five liters whilst the general population would feel it when it's at 10 liters.

So it's not in your head. You're really feeling it more, so it's different. And then the usual recommendation is to go on the FODMAP diet, which eliminates fermentable food, which reduces bloating and that kind of stuff. But I'm careful with this because I tell them that's an option. You could avoid all these foods, but the problem with that is that you're too sensitive, and if you avoid the food, then you're not getting that stimulation. So what's going to happen the next time you eat it? You're just going to be even more sensitive. So I tend to approach it more like in a cognitive behavioral type approach, and there's over 20 clinical trials that show that CBT works in IBS. So instead of saying, oh, no, coffee gives me diarrhea in the morning, it says, well, that's great. Coffee regulates me in the morning. I can dose my coffee, and then in the rest of the day, I'm fine because I've taken care of it with my coffee. So just changing that mindset might actually help them and maybe not need medication for their IBS.

Dr. Mariam Hanna:

That's actually brilliant. This kind of represents a recent shift in our thoughts towards the management of IBS. What about the management of those that don't have typical reproducible symptoms? How can we help them in our clinic other than saying it's non-IgE mediated?

Dr. Philippe Begin:

So the best way is to do a food challenge and ideally a placebo-controlled challenge because even if you tell them they don't have allergies, they do feel the symptoms and the connection is so strong. So what I do is that I usually give the first dose of the challenge for these patients going to be placebo. It's just your brain made that connection. It's a fight or flight reaction. So you're protecting yourself. It's actually inducing the symptoms because oftentimes, especially if they have a tendency toward urticaria, they can induce hives, they can induce wheezing, but it's all stemming from that adrenaline, that they get from the stress when they see the food. If you want to tell the patient ahead because you feel medically legally it is better that way, it's fine because I find that even if they know that it could be a placebo, just the fact that it could be the actual food they're allergic to, that's going to trigger some anxiety, and then that anxiety that they'll feel will validate that. So the only group I'm more careful with is those in which I suspect malingering. So this is actually really rare. Most patients, they don't have any bad intentions, and they really do feel the symptoms. But if that's the case, then I would tell them before that there's potentially a placebo, but usually those patients will just not come to that appointment.

Dr. Mariam Hanna:

That's challenging. Let's talk about our chronic urticaria patients with regards to food allergy. How often is this a concern or a question, and how do you approach it?

Dr. Philippe Begin:

So what I find useful is when I realize that this is going to be a chronic urticaria case, then usually you listen to the patient first, but I switch it around with these patients. I tend to give them the answers before just to show them that I know what I'm talking about. Those in which it's a bit trickier are those that don't actually have chronic urticaria. They don't have urticaria for six weeks. I call them subclinical CSU patients, or I guess you could call them episodic. It's not typical acute urticaria where you get that episode and then it's gone. But they get multiple episodes of acute urticaria with the same trigger like infection or COVID vaccine two weeks after a COVID vaccine is quite classic. So they get these bouts of hives. So because it's punctual like this episodic, then they can think it's food allergy. But when you really do the careful history, there's no clear relation with food, and oftentimes it's still going to last a bit longer, like two or three days, which is not typical for food allergy.

Dr. Mariam Hanna:

So I do want to flip to the management of IgE-mediated food allergies, particularly as it comes to counseling adults or managing adults, and we're going to draw some similarities and differences between what we do with adults as well as pediatrics. So how do you counsel patients with new onset IgE-mediated food allergy?

Dr. Philippe Begin:

Yeah, so there are some differences biologically speaking and psychosocially speaking. On the biological level, they're bigger, they have bigger stomachs, so they can pack more foods than children. So you'll get less vomiting, and you'll get a reaction. Oftentimes that patient has had a lot of food in your challenge when they start reacting. And the consequence of this is when they do start reacting, they react strongly because there's a lot of allergen. The other thing that's bigger is your blood vessels. So if you dilate a bit, your blood pressure is going to drop more rapidly in adults than in children. So we get less hypotension, but it's usually a healthy population, so they usually compensate that hypotension. So one thing you need to be aware of when you're doing food challenges with adults is that if your first epi and second epi don't work, the next thing you need to do is flush volume.

So it's a distributive shock. So you may need to give as much as five liters of volume, but it's not only for patients that are in shock. Even if the patient is normotensive, he might be clamped. So your epi that you injected in the thigh is not being absorbed. So classically, these patients, they keep wheezing, they have the hives, you flush your normal saline, and all of a sudden it all clears up. So you weren't giving it for the hypotension, there was no hypotension. You're giving it to help absorb your epinephrine. So those are some biological differences. The other big differences are more on the psychosocial part of it. So dealing with a food allergy for a patient is also dealing with the risk of accidents, and we don't manage risk the same in children as we manage it for ourselves. When it's your children, you're actually not willing to take any risk.

So you're extremely risk-averse. As an adult, we're entitled to make bad decisions, and that's okay. So when you look at adults, you need to see it from that point of view and really put yourself in the internal aspect. When you have lots of patients that don't follow our advice, it's fine. We still care for them. So on the adult side, I really see two different types of patients, those that are afraid and those that are not afraid. And typically those that are afraid are those that haven't had that many accidents. They don't have the experience of the reaction. Paradoxically, those that are less afraid are those that had lots of reactions, including some anaphylaxis, and I call them expert reactors because they've had so many reactions that they know what to expect, and they almost become, I say they have this experiential knowledge of their reaction because they felt it and they can tell you, I'm with my parents and we're having dinner and I'm starting to have a reaction.

My parents are flipping out saying, oh, you need to give epi now. Go, go, go. And I say, no, no, it's fine. It's only itching. I know when it's going to go to an anaphylaxis. We're not there, but they won't listen. They absolutely want me to get the epi, and it frustrates me incredibly. So I validate that it's true that you do have the sequence inside an individual patient that's repeated every time. And it was actually published by Peter Vadas in Toronto looking at patients that went to the ER. When you look at different episodes of anaphylaxis, the patients had the same sequence, they had the same symptoms, and we see that when we do challenges, sequential challenges in studies. What does change is the threshold, the amount of food that made you react because of co-factors, but the actual sequence of symptoms is usually quite reproducible.

So patients can use that. And one example that I like to tell about is this patient who had multiple food allergies. He's 22 and he's at this team-building experience with this new job that he has. He doesn't know anyone. There's 50 people and they're cooking food, and at the end, they get this cake. So he sees the cake. He told them he had his allergies, and then he starts eating. He says, oh, shoot, there's peanut in there. I know there's peanut. So what he does, he tells only his boss because I told him, when you have a reaction, you need to tell someone. That's a mistake that adults do. We don't want to bother people when we're adults. Children will always tell adults something's wrong. We don't want to bother, so we'll just walk outside and not tell anyone. So he went and just told his boss, and then they went to the back and then they looked at the box for the cake.

And indeed, there was peanut in there, not just may contain. It was literally one of the ingredients. And then he starts feeling symptoms. He says, I know exactly what's going to happen next. I'm going to start wheezing, then I'm going to have to give the epi, call the ambulance. Then I'm going to go out in the ambulance, and then those 50 people, whom I don't know, will all know that I am severely allergic. I will be the guy with the allergy that had the terrible anaphylaxis for the next 25 years. That's how I'm going to be labeled. I don't want that. But I had told this patient that he was allowed to give the epi and not go to the ER if he felt comfortable. So he said, I was so happy that you told me this because I gave myself the epi. I waited 15 minutes with my boss, everything went away. So then I just walked back in and enjoyed the rest of the activity without anyone else knowing. I actually had a reaction apart from my boss. He said that was a total game changer for me. I felt I was actually controlling my condition. It wasn't controlling me. And for adults and teenagers with food allergies, I guess to a certain point children also, having an allergy is really an issue with not controlling your body and what's going to happen. So just giving them that option for that patient, it made a huge difference.

Dr. Mariam Hanna:

I really like that story. But I'm going to take you back. I want to dig into a couple of different things you said. So first, in regards to anaphylaxis presentation, one of the common things that still is very pervasive in clinics is that the severity is unpredictable from one reaction to the next. In patients, you were saying the sequence of symptoms can sometimes be reproducible in a particular patient. Did I catch that correctly?

Dr. Philippe Begin:

Yes, exactly. So you could react to a lower dose or react more strongly to the dose you're having, but the type of symptoms you will have tends to reproduce over time. So the patients usually can tell where it's going, or if it's not there yet, it might get worse eventually, but they'll see it coming, especially if they've had the experience. If they've never had the experience of having it reproducibly being the same thing, then obviously you can't trust that. But if they tell you that they know, you can trust them.

Dr. Mariam Hanna:

So this is particularly in a patient with lots of this experiential knowledge about having gone through multiple reactions in the past. This could be said for patients that have been on immunotherapy and have unfortunately had reactions on immunotherapy or just ones with hard-to-avoid allergens where accidental exposures may be more ubiquitous or common. So this is from an allergist that does many, many different food challenges and sees many different patients, kids and adults with food allergy. So does every reaction progress to anaphylaxis?

Dr. Philippe Begin:

No. And that's really something that we need to change in our discourse. Anaphylaxis is the only disease I know that actually has "may cause death" in its definition. How many deaths are caused by anaphylaxis? Very few, much more death by pneumonia or by heart infarct. But when you look at the definition of infarct, it's just dead tissue. It doesn't talk about death. It has nothing to do with death. So this message around anaphylaxis, I think we put it out there because we want it to be taken seriously, but the problem is that it's a bit false. It's misleading. So most reactions will not progress from anaphylaxis. And even those that do progress from anaphylaxis, 80% will get better without any treatment. We know this. And even in those that don't get better without treatment, it doesn't mean that it was severe. You can have mild anaphylaxis, but what an anaphylaxis is, is you're reacting to an allergen that's getting in your bloodstream. So it's getting distributed everywhere, but it can still be a mild reaction that's going to evolve favorably without treatment. You don't need to take that chance because you have epi.

Dr. Mariam Hanna:

Yeah, and I think this has also already started that mind shift change around the management of anaphylaxis and the safety of using epinephrine. Okay, one more. Epi fast. Give me a definition of fast.

Dr. Philippe Begin:

So for me, fast is the moment you have an anaphylaxis. So I tell them, you eat the food. So the way I explain allergies to patients, I explain, you have those landmines all over your body. They're armed. So everywhere it touches the food, you're going to trigger a reaction. So if it's itching in your mouth, if you have a tummy ache—well, I don't say tummy ache with adults, I say that in an adult way, saying it in English, I don't know—anyway, so when I say...

Dr. Mariam Hanna:

...abdominal pain, abdominal...

Dr. Philippe Begin:

Abdominal pain, that's what I'm looking for. So I said, so you have your abdominal pain. That's not an anaphylaxis. That's like my skin test. But in your mouth and your stomach, I put the allergen directly there. You don't have skin, so I don't need to scratch it. It's going to react. But if you start wheezing after having your food, then you didn't breathe in the food. It's not like if there's a cat in the room, you're breathing in, the cat allergen is going to go in your lungs. So you can trigger asthma. You can treat it the same way by breathing in a medication, but if it's triggered by food, then the allergen reached your lung through your bloodstream. So it's already getting all over your body. Your treatment also needs to be all over your body, so you need to inject it. So you actually treat the reaction wherever it's happening.

And that is all over your body. So you just need to follow the food. So if you have hives around your mouth, you don't need to give epi for this. If you have hives all over, it's a good idea to give epi. And you know what? If you have hives all over, don't wait for another system. You don't have the two systems criteria. It's not dangerous to just wait it out, but you're going to have a horrible night. It's going to itch. I mean, the only thing that actually works is epi, because your antihistamine, they will take two hours to have their full effect, and that gives the meh to the patient. It's not a big deal giving epi, you can give it earlier. And even if you make a mistake and you give it for local symptoms that were not anaphylaxis, it's not that big of a deal anyway, but you don't need to jump on any symptom.

Dr. Mariam Hanna:

Okay. So how does your knowledge of how you counsel and manage patients in adults translate when you're seeing the infant with the new diagnosis or the young child with the diagnosis and the family that's trying to cope with this?

Dr. Philippe Begin:

Yeah, so for the young child, I believe that probably in 10 years it's not going to be an option or a weak recommendation. It's going to be a strong recommendation that these patients should undergo some form of immunotherapy, which might be oral, which might be something else. So there's really less of a question. And anyway, parents want you to tell them what's the good decision. As kids get older, then I have a little bit of that adult conversation with them. And when they're teenagers, you need to incorporate this in the dynamic, but you also need to incorporate the parents because you want the parents also to recognize this experiential knowledge because the teenagers are frustrated that their parents couldn't understand why they weren't taking it seriously. And I say, it's not that she's not taking it seriously. It's that she's had this experience and we need to recognize this. And then after that, usually it's better for everyone.

Dr. Mariam Hanna:

It is better for everyone when Dr. Begin helps us to bridge the gaps between pediatric and adult and transitions. And this is a challenging conversation to have. Dr. Begin, you did a fantastic job. It's already time to wrap up. Okay. So time to wrap up today's episode and ask today's allergist, Dr. Philippe Begin, for his top three key messages to impart to patients and to physicians on today's topic: adult food allergy. Dr. Begin, over to you.

Dr. Philippe Begin:

Alright, so the first thing I would say is that the differential diagnosis for food allergy is a bit more elaborate in the adult population, but in the vast majority of cases, you can work it out with a good history, including the timing of symptoms and looking for co-factors. The second thing I would say is for patients with IBS-like symptoms that have no red flags, instead of avoiding the food—and that's my personal approach—I like to suggest exploring a CBT type approach where they attempt to change their perception of the pain and switch it to a positive way and rebuild their tolerance. And then the last message, in the end, the ultimate goal of food allergy care is to empower patients to best manage and achieve a sense of control over their conditions. And to do that in adults, you need to recognize their experiential knowledge and take into account their own tolerance to risk, not yours and certainly not their parents when establishing a management plan with them. And that's it.

Dr. Mariam Hanna:

Fantastic. Thank you, Dr. Begin, for joining us on today's episode of The Allergist.

Dr. Philippe Begin:

It was an absolute pleasure.

Dr. Mariam Hanna:

This podcast is produced by the Canadian Society of Allergy and Clinical Immunology. The Allergist is produced for CSACI by Podcast Productions. The views expressed by our guests are theirs alone and do not necessarily reflect the views of the Canadian Society. This podcast is not intended to provide any individual medical advice. To our listeners, please visit www.csaci.ca for show notes and any pertinent links from today's conversation. The "Find an Allergist" app on the website is a useful tool to locate an allergist in your area. If you like the show, please give us a five-star rating and leave a comment wherever you download your podcasts and share it with your networks because it's all about learning to navigate experiential learning in adult food allergy. Thank you for listening. Sincerely, The Allergist.