Dr. Wesley Burks discusses peanut allergy in this second episode of our Conversations on Food Allergy podcast series. Dr. Burks addresses anxieties families have concerning peanut allergy, how to respond to a reaction, and describes the current research and treatments. Dr. Wesley Burks is the Curnen Distinguished Professor in the Department of Pediatrics at UNC and he is the Executive Dean for the School of Medicine. Dr. Burks is a pediatric allergist and immunologist and sees patients at UNC who have food allergies, and is the Executive Director for the UNC Food Allergy Initiative.
– Dr. Burks on peanut-allergic reactions
Ron Falk, MD: Hello, and welcome to the Chair’s Corner from the Department of Medicine at the University of North Carolina.
Today’s episode is part of our series focused on food allergy; and we will be discussing peanut allergy.
We welcome Dr. Wesley Burks who is an expert in peanut allergy. Dr. Burks is the Executive Dean for the School of Medicine. He is a pediatric allergist and immunologist and sees patients who have food allergies. We’re really excited that he is here today. Welcome, Wesley Burks.
Wesley Burks, MD: Thank you, Dr. Falk. It’s nice to be here.
Rise in Allergic Disease
Falk: There’s a lot of discussion about peanut allergy, and we’re learning more and more about it. Many of our listeners have a relative or a friend who has this allergy. Is peanut allergy really becoming more common, or is it something that’s always been there and we’re just better identifying it?
Burks: It’s interesting to look at the last four decades of allergy—allergic diseases in general, asthma, allergic rhinitis, atopic dermatitis and food allergy, because they’re all related. What we’re seeing in food allergy is a tripling in the last two decades of the disease; peanut allergy actually parallels that. It’s the third most common allergy as far as foods in the US with milk being the most common and egg second. What you hear in the public is that peanut is often the one that’s associated with life-threatening or life-ending disease, but it’s not the most common food allergy that we see.
If we compare to the 1980’s, again the prevalence is significantly different, with the same way to diagnose them, with doing a food challenge to prove that you’re allergic—so there is a real difference.
Falk: Why? What’s triggered this?
Burks: I’ll digress for a second. If you go to a lecture about diabetes, or autoimmune diseases, or allergic diseases, the people presenting those diseases, their first five or six slides are the same. They talk about the environment, they talk about the change in the microbiome, the diesel particulate exhaust, change in other behaviors that we see in the industrialized Western society. All of those diseases I see as immune-related diseases have seen changes in the last couple decades that we don’t see in the non-industrialized societies. Food allergies are just one of those that are much more common now than they were several decades ago.
Falk: There is this hypothesis, roughly termed “The Hygiene Hypothesis,” that would suggest that in fact we should be exposed as infants to dirt, to the environment, and that the rise in these diseases is that we have avoided our environment and a dirty environment when we were kids.
Burks: That hypothesis was really put forth in the late 1980’s, and there are some really good studies in Eastern Europe from the late 1990’s, early 2000, in East Germany, taking families that had grown up on a farm. You have to really dissect out what the differences are, but basically the families that had kids that grew up in the farmhouse, with a cow literally in the kitchen, who were exposed to endotoxin and other bacterial contaminants really do have a different prevalence of disease.
Falk: Much less.
Burks: Much less. How that relates though, to what we might see here in the inner city which is really not a clean environment but it’s different than a cow in the kitchen in East Germany, we don’t see the decreased prevalence in the inner city. So, it’s not just cleanliness—it’s specific things that are introduced early on in life that really change our immune system, and the hygiene hypothesis is what I alluded to earlier, with the microbiome, diesel particulate exhaust, all those things playing a part. I don’t think there is one reason, I think it’s a combination of them that is ongoing.
Falk: Everyone should take their kids, move to a farm, and roll around in the dirt. If you are concentrating on peanut allergy, are there specific risk factors that separate out those people who have peanut allergy from milk allergy?
Burks: Not really, the risk for allergic disease is inherited—allergic rhinitis, food allergy, atopic dermatitis together. So, if you have a parent that has one of those diseases, the child has a forty percent chance of having one of those diseases. If the mother has asthma, the child might have allergic rhinitis. If you have both parents, or a parent and a sibling, it goes up to about sixty percent plus, and the parent might have asthma and the child might have food allergy. It’s allergic disease to allergic disease, that’s the biggest risk. The only slight risk for peanut allergy is if another family member already has it, then there’s a slight increase, but most of the inheritance is allergic disease to allergic disease.
Falk: If you’re a parent who has asthma or allergic rhinitis, let alone both, your kid has a much higher chance of having food allergy.
Burks: Or any of the allergic diseases, including food allergy.
Allergy Immunotherapy
Falk: There are a number of efforts to try to decrease the possibility of your child having a reaction to a peanut or to milk, and there has been a lot of work which you are doing much of, of immunotherapy or if it isn’t immunotherapy, then tolerance to a food particle. Can you tell us about that?
Burks: If a family has a child with allergy, specifically peanut allergy, they live in fear that their child will accidentally ingest peanuts at home, in a contaminated food when they go out to eat, at their grandparents’ house, and they have a life-threatening reaction. The chances of that happening are relatively small but they’re unpredictable. So, what the family wants is some protection from an accidental significant reaction.
Studies are done with types of allergy immunotherapy. Immunotherapy has been done for over a decade for allergic rhinitis and asthma, for airborne allergies like grasses and tree pollen, and basically the concept is to give that person back what they’re allergic to in increasingly larger amounts over time to change their immune system.
Falk: Allergy shots.
Burks: Right, so those are the injections that people get, you grew up with kids getting shots. The concept of allergy immunotherapy we took to foods to give them what they’re allergic to, to try to raise their tolerance level. As an example, most children who are allergic to peanuts will react to about a third of a peanut, so not very much. If you do a type of immunotherapy, whether it’s oral, or sublingual, or epicutaneous, at 6 months to 12 months into it, they’ll tolerate somewhere between 5 and 20 peanuts before they have a reaction, so their tolerance level goes up, but only while they’re on the therapy.
Falk: Why can’t you do a peanut allergy shot? Why does it have to be oral?
Burks: If you look at allergic disease in general, the most likely way you’ll cause a really bad reaction is by giving something IV, and then intramuscular injection is the next way to cause anaphylaxis or a life-threatening allergic reaction. The least likely way to give a reaction is to give it orally, so we’re trying to take the safest way that you can give peanut back to cause the changes in the immune system. People have tried injection with peanut immunotherapy, there were studies in the early 1990’s and there was a patient who died from that. There’s a resurgence now with a modified peanut to try to do that, but just in general whether it’s a drug or a food, if you give something intramuscularly or IV, you increase your chances of having a really bad reaction significantly.
Falk: So what you’re doing now is literally grinding up peanut and putting it between the cheek and gum?
Burks: No, we actually buy peanut powder from an international candy company, and the powder has some other things in it. We weigh it out and give it to the patient mixed with food and that’s the dose that they take that day.
Falk: They drink it?
Burks: They put it in a food, in applesauce or ice cream or something soft, and eat the food. The amount that they put out and the regulations for it are not different than you might expect for a drug, because we’re giving them something to change the immune system, so the regulatory hurdles that we face as far as how to give the peanut product—we don’t just buy a product off the shelf and give that to them. We have to make sure it doesn’t have bacterial contamination, we have to make sure it has all the peanut proteins in it, all the things that you might do if you’re giving someone a drug like amoxicillin—it’s the same process, it just happens to be a food.
Falk: How successful is it?
Burks: There are different types of immunotherapy—there’s oral, sublingual—liquid concentrated peanut, and there’s a company that has an epicutaneous one which is a patch. The main ones we’re studying here are oral and sublingual. The oral—about fifteen percent of children cannot tolerate it because they have such significant GI symptoms in the first few weeks when they start it. If they’re in the 80 plus percent of those who can tolerate it, most all of them will get to that tolerance level in six months where they can tolerate it quite easily.
The sublingual is to take peanut and put it in liquid. That liquid concentrate is taken with a dropper and put under the tongue—four, five, six drops put underneath the tongue. They try to hold it for a couple of minutes and then they swallow it. That’s a traditional form of allergy immunology that’s used for grass and tree pollen and other things, it’s been done for a long time. There are products approved in the US for sublingual therapy for grass, weed and timothy grass, and that changes your immune system like it does for oral and epicutaneous. It has fewer side effects than oral and it’s more effective than epicutaneous, so it’s kind of a midpoint between those two types of treatments. All of them, the effect begins to go away once you stop the treatment. If you were treated for five years, unless you continue to expose them to peanut in some way, it begins to wear off. It doesn’t wear off as fast as people thought. Dr. Kim and others have done studies that have shown the decay in that protection, and it’s longer than people thought, but it will dissipate over time unless you continue to allow them to, what I think of as “see the peanut” in some way.
We’re not asking them to ingest peanuts, but it gives them a level of protection that they’re not going to eat six peanuts.
Falk: Because that’s the fear—the fear is that you go to somebody’s house and they have peanuts and some way or another, unbeknownst to the individual they’re eating peanuts. It’s not an effort to allow someone to eat peanuts again or for the first time, it’s an effort to protect them of a catastrophic adverse moment.
Burks: Yes. One of the interesting things that I’ve learned personally is that a lot of us started doing this, we did it to make the disease go away. That’s what you want to do, you give them a treatment and make it go away. What we quickly realized, literally the first year, the parents really didn’t care about that—all they wanted was that protection, and they’ll do a lot to raise that threshold so their child won’t have an accidental reaction. They didn’t really care that their child couldn’t have peanut butter and jelly sandwiches, but they did care that there was that threshold, so it really changed our approach. Those are really different goals.
Dealing with Anxiety About Allergy
Falk: Right. If you’re a parent listening to this discussion, and you have not had the opportunity of immunotherapy, and you’re reasonably concerned that your child has a peanut allergy, what do you do to make sure to the best of your ability that you can protect your child? You can’t keep them in a bubble.
Burks: I think that what I talk about with a family—if their child is two or three or maybe seven or eight, ten or eleven, or high school or college, each discussion in that age range, and depending on the child and what they can tolerate. I had discussions in clinic this week with two young adolescents, at that point they can really begin to know and own the disease. When they’re going out to eat, they can say “I’m allergic,” and they can help, and the more they can do that, the more comfortable they are and their parents are.
The big thing to understand in this for a family is that you have to ingest the food to have serious life-threatening reaction—it’s not touching it, it’s not smelling it, it’s not sitting next to somebody in school or a ballgame, the child that is peanut-allergic doesn’t like to smell it. They intuitively know, “That makes me feel bad.” It’s not going to cause an allergic reaction—you have to eat the food. It may only be a quarter or a third or a hundredth of a peanut—it may not take a lot but you have to eat it before you’re going to have a life-threatening reaction. That’s the biggest thing for a family to understand.
Falk: The worry of a parents might also be, “I have a child with a food allergy, a peanut allergy.” What are the chances of another child, a sibling now being at risk. One hundred percent, five percent?
Burks: No, less than the majority of them are at risk. You can tell relatively early in life if the sibling has allergic rhinitis, other allergic disease. They’re more likely to have peanut allergy. If the first couple years of life they have no atopic dermatitis, they don’t have any allergic symptoms, the likelihood of peanut allergy is small.
Falk: Do you introduce peanuts to a sibling slowly, just to make sure this isn’t a problem? Are there guidelines?
Burks: There are guidelines. This is a fascinating history that I’ve seen in my lifetime. When I grew up, in the field the advice and guidelines based on animal studies told us as pediatricians to help people avoid the food—so avoid milk for a year, eggs for two years, peanuts and tree nuts for three years. I was around when people developed the guidelines. People did that for a few decades and this change in prevalence happened, and people began to study that and the opposite of introducing allergenic foods in the first four to six months of life. A landmark study was done about three years ago in London, and the international guidelines have changed.
If you have a child who is not allergic to anything else, no allergic family history, give them peanut butter—not peanuts—at four to six months. If you have a child from a family that has allergic disease, unless they’re not having allergic dermatitis or another risk factor, give them peanut butter at four to six months. The last one would be if you have a family that has another peanut allergic child, and they have allergic dermatitis, they can be tested with either a skin test or blood test. If it’s negative, give them peanut butter. All three of them, once you introduce peanut in their diet, they’re not going to develop peanut allergy later on.
Falk: And it doesn’t make any kind of difference what kind of peanut butter it is?
Burks: No. The interesting thing about that is, there are differences in peanut oils. This may be more than you want to know at this point, but it does make a difference to families. Chick-fil-A, one of our favorite places to eat, uses peanut oil to cook in, so for a family that is acquainted with peanuts, this peanut oil is actually heat-processed so all the protein’s gone and you can’t have a reaction unless the protein is there. If you go to Carrboro, to the health food store, and they make peanut butter by grinding up peanuts with a mortar and pestle, then the protein will leech into the oil—that’s cold pressed. That peanut oil does have protein in it. It’s important for families to understand that.
Falk: So the cold-pressed variety, that is a risk?
Burks: It has protein in it and you can react to it.
Falk: So heat killed or cold pressed are very different. That’s an interesting difference.
The Future of Peanut Allergy Research & Treatment
Falk: Where’s the research headed?
Burks: Three big things. One would be a treatment that would give families the comfort level that their child has some protection from an accidental reaction, because that’s really their main anxiety about all of this. A treatment that has fewer side effects than what we have now, and a treatment that you can continue to expose them to the treatment bur it’s not really a daily treatment like it is right now—so the first part is trying to change the treatment from where we are right now.
The second part would be how we understand the mechanism of the treatment that would allow us to do something different, a generation or two generations from now. Any study you do, as you well know, if you design it appropriately, whatever answer you get is really good because it informs your next study. If it’s a result that’s not as positive as you want, if you do the right mechanistic study or laboratory study with it, you can do something better the next time.
The third area would be, “How do you identify a peanut-allergic patient that really is at risk for life-threatening disease?” Not everybody is. It’s a really small percentage of children who have that, and right now we can’t tell that person from the next one. Everybody lives in fear of a severe, accidental reaction. Even in all of the peanut-allergic kids, particularly those in the first few years of school, is really, really small.
It’s interesting to think back a few decades about therapy with families and the dichotomy of what they want and what we thought they would want. I think that most families now understand it as a situation of equipoise. We have some treatments that will become available in the next three or four years, therapy is in Phase III studies, the epicutaneous we talked about is in Phase III and will likely be approved. If you are a child of a five-year-old who has peanut allergy, your child goes a year and a half before they have an accidental reaction, they don’t have symptoms every day, but you live in fear every day that they’re going to, if you put both of those treatments with side effects and you have to do something every day, if you’re giving them oral immunotherapy and they’re having hives or wheezing and you’re giving that protection from an event that doesn’t happen very much. You have to think about, what’s really your goal out of thinking that they need treatment. It’s an important thing to think about, as treatments are approved, it will be an individual parent-family discussion. What are they most concerned about and what’s the most likelihood, treatment or not treatment that will address those concerns?
Falk: Is there any research, other than the study in eastern Europe with the cow in the kitchen, is there an effort to determine what you need to expose your infant to, to decrease the possibility of allergic symptoms?
Burks: There are relatively good studies throughout the world. There are some better ones being done in the US, in rural Wisconsin, some in Australia—to try to identify the factors that might play a part in decreasing the likelihood of that child developing allergic disease. They really take decades to play out, because you need to look at the outcome and it’s not a year or two-year outcome.
Falk: So for now, everyone should bring a cow into their kitchen..
Burks: Right. For the kids.
Responding to a Reaction
Falk: If you’re watching your child have a food allergy, in this case a peanut allergy, what should you do?
Burks: The types of symptoms that a child will have from a peanut allergy reaction are skin, GI and respiratory. The skin symptoms are hives, itchy rash. GI symptoms are vomiting, really severe abdominal pain, and respiratory symptoms are, “my throat feels funny,” or start to wheeze, cough will be part of that—that’s the constellation of symptoms. Each of us that take care of food-allergy patients—peanut are a little bit different, but it’s a general category—if you eat something and you feel like it has peanuts in it and they have a hive or two on their face, they’ll take the antihistamine. If they have symptoms really from their chin, throat down, “my throat hurts,” or they start wheezing, coughing, hives all over, start to have vomiting, they need to take their epinephrine and seek medical care right away and not wait at home for it.
There are some that might suggest if the child eats something and you know it has peanuts in it, give the epinephrine right away. I wouldn’t do that. I think if you wait to see because you might suspect that it’s there but it isn’t. If you have symptoms from your chin, throat down, that can be life-threatening so take the epinephrine and antihistamines and go see the doctor.
Falk: It’s an EpiPen or an injectable form of epinephrine and an antihistamine like Benadryl for example. But the other message is not, if you have two systems, skin and respiratory, skin and GI, you probably need to take the epinephrine and go to the emergency room.
Burks: Yes. It’s interesting that most of us feel like the skin symptoms are a harbinger of something bad, but then probably 75-80% of the life-ending reactions do not have skin symptoms, they’re respiratory symptoms which is why the adult who will have a life-threatening reaction is basically an asthma reaction.
Falk: So respiratory symptoms alone, skin symptoms or not, time to take the epinephrine and go to the emergency room.
More Resources on the Web
Falk: If you were to give advice for a trustworthy source of information on the web, any thoughts?
Burks: If you Google peanut allergy, you’ll get a million hits. For a family that has not been seen and given good information, then it will be really scary for them and they’ll get a lot of misinformation. There are two sites that I would recommend. One from a lay organization called FARE, Food Allergy Research and Education and that web site is foodallergy.org. Then the UNC web site for the Food Allergy Initiative. Those are both good. The FARE site has everything from how to diagnose, to recipes for families. The UNC web site is about the studies being done here and other places.
Falk: Thank you, Dr. Burks, for this wonderful amount of information.
Burks: Thank you, it’s good to talk to you.
Falk: Thanks so much to our listeners for tuning in. If you enjoy this series, you can subscribe to the Chair’s Corner on iTunes or like the UNC Department of Medicine on FaceBook. In our next episode, we will welcome Dr. Scott Commins and have a discussion on meat allergy or alpha-gal allergy. Thanks so much.
Visit these sites for information on peanut allergy.
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