Transcript of "Food Allergy" Podcast
Josh Davidson, MD: Hello and welcome to the National Jewish [Medical and Research Center] podcast series. My name is Josh Davidson, a fellow physician here at National Jewish and I'm here with Dr. Kirstin Carel, faculty physician at National Jewish. We're here today to talk about food allergies. So, thanks for coming.
Kirstin Carel, MD: Thank you for having me.
JD: The focus basically for this section will be addressing some of the topics that parents often bring up in clinic visits and to address some of those questions. So I think one of the first questions is to address what is really a true food allergy?
KC: It's really a process in the body mediated by what we call an allergic antibody and usually you'll see reactions like hives on the skin or swelling of the lips or eyelids or ears. Immediate vomiting within a couple of minutes to thirty minutes of eating what they're allergic to or even trouble breathing or trouble swallowing because the throat is swelling in what we call anaphylaxis. It does not include things like lactose intolerance or celiac disease which are more intolerances to food but not allergy-driven.
JD: So, if I'm a parent, and let's say I notice a reaction in my child, what kind of things would help me differentiate between the two, between those that are more intolerance versus the allergy per se.
KC: Allergy tends to be more hives or swelling of the face or hands... vomiting within a few minutes after eating, trouble breathing or trouble swallowing, versus someone with lactose intolerance who may be really gassy and have just stomach pain but not necessarily vomiting. Celiac disease you may have more diarrhea and stomach pain. Another sign of food allergy can be eczema that can be hard to get under control.
JD: Okay. And is there a time difference with the course as well? As far as differentiating between the two?
KC: With an allergy, you're typically going to see symptoms within thirty minutes. With celiac disease or something like lactose intolerance, it may be a short time course, and it may be further out or a problem with prolonged and continued stimulation. With celiac disease, with things like wheat ingestion, they can be over a longer period of time.
JD: Great. Now as far as food allergies go, it's obviously a pretty selling topic currently.. are there any foods currently that are more associated with food allergies?
KC: For adults, it tends to be peanuts, tree nuts, fish, and shellfish. For kids, the most common are really eggs and milk; the peanuts and tree nuts still come in to play, and then we do have a number of kids that are allergic to soy and wheat. Typically, we ask kids that are already allergic to stay away from things like fish and shellfish until they're three years old so we don't see that happen as much.
JD: Again, as a parent, let's say I'm concerned about my child having food allergies and I decide to bring them in to see an allergist, or even a general family practitioner or pediatrician, what kind of tests might I expect to see?
KC: There are two tests that are really helpful. One is a skin test-or a scratch test-where we actually scratch a drop of solution that has the protein from the food we're interested in in it. We scratch it on there, we wait fifteen minutes, and then we measure any bump that appears. Your child can't be on allergy medicines for a few days before doing this test because that interferes with the body's reaction. And another test that we find really helpful is a blood test, and that looks at how much antibody that's specific to you're child's allergies-so to either egg, or milk, or peanuts-how much of that antibody they have in their blood. And that gives us a sense of if you're child's actually at a point where we can challenge them to that food in our office and also gives us over time a chance to track to see if the allergy is going away. In other words is the number falling over time. So I usually check the blood-work every year or so.
JD: Good, so the two together are helpful.
KC: Yeah. Now, the only true 100% test is doing a challenge in a doctor's office where we start with a small amount of the food that you may be allergic to and watch carefully for symptoms and if things are going well, we gradually increase the dose. Usually that takes three or four hours to get to a full dose, but there are some kids who won't have a reaction until they're, say, drinking a full glass of milk versus drinking a teaspoon, so it's important to do it in a gradual manner and under safe conditions so that if your child does react, particularly with an anaphylactic reaction, we can intervene quickly and for that reason we don't usually advise doing challenges at home.
JD: Right, I think that'd be a good idea. One of the major foods, as you know, that comes up is peanut allergy and I think that regarding peanuts, one question that often comes up is "when one is allergic to peanuts, is one allergic to all nuts?"
KC: Right, and not necessarily. And we can do specific scratch tests and blood tests for the other tree nuts to figure out what the relationship there is. Probably about half of the kids I see that are allergic to peanuts are also allergic to another tree nut or a seed. The interesting thing about that is peanuts are technically not tree nuts because they're grown in the ground, they're more related to a class of food called legumes, which are like beans and peas and that sort of thing. But we don't see much cross-reaction with peanuts and green beans or peas-it's only about five-percent-but when a child, particularly a small child, is already allergic to peanuts, we generally advise staying away from the tree nuts until they're older. One reason is that children, and even some adults, are really not reliably able to distinguish between which tree nut is which. The other reason is that we don't want allergies to develop, particularly in someone that's under the age of three. The third reason is that there's a lot of potential for cross-contamination, particularly when you're dealing with things like candies, where you may have cashews, walnuts, and peanuts all being processed in the same factory. That's why you see on a lot of food labels no indication that it contains peanut, but they may say that it contains traces of peanut or traces of tree nuts because it's manufactured in a factory that also handles tree nuts. So there're a few reasons why we have concern about cross-reactivity.
JD: It seems like that would be particularly tough with nuts, since they're so omnipresent in so many different foods.
KC: And with tree nuts, if you're allergic to walnuts, you're also highly likely to be allergic to pecans, if you're allergic to cashews, you're highly likely to be allergic to pistachios, because they're closely related. We've also started looking more closely at seeds, like sunflowers seeds, poppy seeds, that sort of thing because there seems to be some relation between tree nut allergies and seed allergies, for some patients not all. Many patients probably eat seeds just fine, but it's now something that we're getting more used to actually doing skin tests for to see if it's a problem.
JD: You had mentioned that delaying and waiting until age two or three for nuts... I think as far as egg is concerned, it's something that kids are exposed to at an earlier age as a softer food or when they're starting to tolerate solid foods.
KC: Right, and the American Academy of Pediatrics actually recommends that you don't introduce egg until age two, but for the reasons you said-it's a soft food, it's easier for a younger child to eat-they often get introduced to it earlier. So often, the first sign we see of a food allergy is when someone's given the child egg when they're thirteen or fourteen months old and they have hives all over their face and their lips get puffy and they came in and we identified other things, like peanut, that they're allergic to as well.
JD: In regards to cow's milk, another one of the big players as far as food allergies go and also another one that might be introduced around age twelve or ten months, here's another common concern that relates to that and cross-reactivity, which seems to be a common theme among these foods and with cow's milk. Soy milk comes up and we know that that's an issue as well with regards to tolerance and changing formulas and things. I think that's a helpful concern to address.
KC: So if your child is milk-allergic, we usually look at soy to see if there's an allergy there or not because, you're right, soy milk and soy formulas are good substitutes for calcium and the other nutrients that you'd be missing out on from cow's milk. Now, with soy milk, it doesn't seem to be much of a cross-reactivity, it just seems to be more of if you're allergic to one food, it's not uncommon to be allergic to another food. And so we want to make sure that we're giving your child something that's safe. There've been studies looking at goat's milk where 92% of kids who were allergic to cow's milk were also allergic to goat's milk because they're very similarly related. However, when they looked at mare's milk from horses, only 4% were allergic. Now, mare's milk is probably a lot harder to get than soy milk or rice milk, so my advice would be a better option. With both of those it's probably important, if your child's not drinking a lot of it, to be talking to a nutritionist as well and make sure that you're getting enough calcium for building strong bones. But soy milk for most kids is a good option as long as they're not allergic.
JD: I think one of the universal questions with food allergies and the answer is certainly different for each of these foods is "will my child outgrow it?" You're told your child has an allergy and you need to avoid peanuts or milk or otherwise and I think it's a good question.
KC: The evidence shows right now that the majority of kids, probably 80% or more, that are allergic to milk or egg will outgrow that by the time they reach age five. It seems to be quite the opposite for peanuts and probably tree nuts as well, where maybe only ten or fifteen percent are going to outgrow that. But I think it's still worthwhile to recheck skin and blood tests every year or so, particularly for things like egg or milk which are harder to avoid, because when you can get those back in the diet, that makes grocery shopping and just life in general a lot easier. If you happen to be one of those lucky kids that does outgrow peanut or tree nut allergy, that also helps, because it makes you less likely as a parent less worried about sending your child off to school and having to have the epipen around all the time and that sort of thing. So it's definitely important to realize that some kids do outgrow it. For some foods, it is more than others, but it's worthwhile relooking at things and not thinking that this is going to be a lifetime problem.
JD: I think as a sort of secondary question to that, once my child outgrows his or her milk allergy, is it dangerous to give them a whole glass or are they essentially cleared?
KC: That's why we do a food challenge, and in a food challenge we go up to what a full serving would be, so that we're sure that even with a large amount you're not going to have a reaction because we do get kids once in awhile on food challenges where they pass through the lower doses just fine, but you get to that full glass of milk or one and a half scrambled eggs, and that's when you see the hives or the swelling start. For some kids, it seems to be more the amount of what they get rather than just an exposure.
JD: As kids, we get a little bit older and enter school or even at a younger age a day care environment, and this issue of food allergies arises and it's quite common to be concerned about the environment parents are sending their children in to. What's your experience been as far as schools and day care?
KC: Well, most of the time now, schools and day care realize that food allergies are so common that your child is not going to be the only one there that has a food allergy. If your child does happen to be, then you want to do a few extra steps as far as educating his or her teachers and the school nurse or health aid that happens to be there. But I would say that in most schools, there's probably more than five or ten kids that are allergic to something. It may be different foods, but the most important part is having a plan for the school and the school's going to require you to fill out paperwork anyway as far as having Benadryl, or having an epipen, or a twin jet, or epinephrine use available, but talking with the teacher and whoever is in charge of the health office or letting them know what your child's typical reaction is when they accidentally get a hold of something-do they just get mild hives or do they have a really severe reaction, have they passed out before, do they have asthma as well because those children are at risk of a more serious reaction. But make sure that they have the Benadryl, the epipen, make sure you're comfortable with where it's being stored, that it's in a place where they can easily get to it if your child's having a reaction. And then talk with them about what they do in the cafeteria or during their snacks and their breaks.
Is this a school that's peanut and tree nut-free? There aren't many schools out there that are milk and egg free because that's really hard to do, but talk with them about what things they typically serve and figure out what your comfort level is. Do you want to pack your child's lunch and snacks every day so that you're sure that whatever they're ingesting is definitely things you normally give them, free of whatever they're allergic to? Or do you have confidence in the people serving your child that they know he/she is allergic, that they shouldn't give him scrambled eggs or whatever it is? So part of it is a comfort level and educating them, and there are some schools that are doing different things now. I've had a couple schools recently that instead of having a peanut-free lunch table where the kids with peanut-allergies sit, there's a peanut table where the kids who brought peanut butter sandwiches have to go to be able to eat them, or they can't eat them. Especially with peanut allergy since it's that common, and like I said, there are some schools that are peanut-free, but that gets to be a little bit of a slippery slope. In other words, if you make a school peanut-free, does it also have to be tree nut-free, and then the kids with egg allergy; what do you do about them? So, there're some schools that have done it, but it's more of a case by case thing and I'm not sure it's realistic to expect every school to go peanut and tree nut-free. But there are definitely daycares out there that are, so if you're concerned and you have the ability to look at different ones, if that would make you more comfortable, I think that's worthwhile doing. I guess that's about it on that topic.
Oh, other things, just because we were going to talk about the safety of your child with food allergies. Making sure your child has a medic alert bracelet on. So say they're on a school field trip and they accidentally get into some food they shouldn't have and they pass out, and there's some random person that gets to your child sooner than the teacher, who could be further ahead or further behind. At least that person can look at the medic alert bracelet and say, "Oh, this child has a food allergy," and then look in their backpack for their epipen or grab somebody's attention because then they know maybe what the most common problem might be and how to intervene. That's the biggest thing you can do for your child. I worry about kids that are closer to two or three years old having a medic alert bracelet just because of the hazard of potentially taking it off and swallowing it, but certainly once they're four or five, if you educated your child well, they know to leave it on. And there are all sorts of medic alert tags out there now; there are some that are very trendy, that kids want to wear.
The other important things are when you go to a restaurant, make sure to inform the waiter and ask them to tell the cook that your child is allergic to whatever they're allergic to so they can take precautions when they're in the kitchen. Say your child is allergic to fish. Well, they don't want to use the same utensil to flip your child's hamburger that they just used on the fish that's next to it on the griddle. Really, have Benadryl and an epipen available at all times, especially when you're going out to a restaurant, when you're away from home. But also know that if you use epinephrine, because your child's having trouble swallowing or having trouble breathing, that you do need to call 911 because sometimes kids need another dose of epinephrine or some other medications that only people in the ambulance would be able to provide. So you want somebody on the way. If your child looks great when the ambulance gets there, that's fantastic, but in case they're still looking bad, you want someone else on the way that has more expertise and can help you handle the situation.
JD: So overall, a theme of preparation, whether it's at school, home, or a restaurant. Call ahead and make sure your medications aren't expired, especially in the case of epipens.
KC: Absolutely, and that you haven't left the epipen in the car in extremely hot or cold conditions because that epipen can degrade a lot more quickly that way. They've actually done a study proving that. The other thing is when you're traveling, on the plane or on cruise ships, to get through security with the epipen, you usually need a note from your doctor, and that's easily provided because most of them have a form they just print out and the doctor signs. But that's so you can carry Benadryl as well, which has been a problem with the limitation on liquids being allowed on planes. Cruise ships-I've had patients that have had very good experiences on cruise ships, and that's because they spoke with the cruise line ahead of time, and let them know what their child needed. They felt overall that it was a very good experience. So that can be helpful. The other thing is just in your own house. Depending on how mischievous your small child is, say your child is peanut allergic but you do keep peanuts in the house for your other children, keep it somewhere where they can't get to it at all. And if you're still having minor problems with hives, or lip swelling, and you're not sure where it's coming from, even though there have been steps to make label-reading a lot easier, it's sometimes worthwhile talking to a nutritionist to go through what you feed your child on a regular basis, and sometimes that helps pinpoint the problem as well.
JD: Especially in children that might have three or four food allergies, where it's particularly difficult to cover recipes and such.
KC: And it's important to make sure that your child's getting enough nutrition. There's a lot of web resources out there that provide a lot of recipes or guidance on what you do when you're trying to make cookies but you can't use an egg in it. Things that you can substitute that are readily available in your kitchen that will give you the same consistency, and the cookies will turn out the same and tasting reasonably good, but it doesn't involve an egg.
JD: Great, well, I think we've covered some good topics and I want to thank you very much for helping out with us.