MR. KOJO NNAMDIFrom WAMU 88.5 at American University in Washington, welcome to "The Kojo Nnamdi Show," connecting your neighborhood with the world. Milk, wheat, peanuts, for most of us, they're foods we can consume without thinking about it. But for a small percentage of Americans, these and other foods can trigger asthma, hives, dizziness, even death in rare instances. Food allergies seem to be on the rise in the U.S., though no one is quite sure why.

MR. KOJO NNAMDIAnd that's particularly frustrating for patients because there are few effective treatments for food allergies on the market. In this hour, we're devoting our weekly segment on food and culture to a discussion of food allergies, including a look at new guidelines to help doctors diagnose and treat these allergies. Joining us in studio is Dr. Hemant Sharma. He is director of the food allergy program with Children's National Medical Center. Dr. Sharma, thank you for joining us.

DR. HEMANT SHARMAThank you so much.

NNAMDIAlso with us, is Dr. Matthew Fenton, chief of the asthma, allergy and inflammation branch at the National Institute of Allergy and Infectious Diseases. He's one of the primary authors of new clinical guidelines for doctors who treat patients with food allergies. Dr. Fenton, thank you for joining us.

DR. MATTHEW FENTONHi, Kojo, pleasure to be here.

NNAMDITime for all of you allergic ones to start calling, 800-433-8850. What is your specific allergy and what do you think causes it? 800-433-8850 or send us a tweet at kojoshow. We sometimes confuse a food allergy with a food intolerance. So let's start with a definition. How do we define a true food allergy, Matthew Fenton?

FENTONWell, in our clinical practice guidelines that were recently published, gets into that difference. The -- from the level of symptoms, food allergies and food intolerances can appear very similar. They're triggered by particular foods, reproducibly generating symptoms. But one of the ways to differentiate between the two is to determine whether the immune response is -- and the type of response that's generated during an allergic reaction.

FENTONAnd that is something we can define through skin tests and blood tests that measure the state of the immune system. And that level of analysis is needed to distinguish between the food allergy and the food intolerance.

NNAMDISo how would I know if I have a food intolerance? Because the measurement would say that my reaction to the food is not representative of an allergy and therefore, how would I define intolerance?

FENTONWell, I think, in the simplest terms, the food intolerance does not involve an immune response as part of the primary mechanism for which you get symptoms. So in measuring or discriminating between the two, we can use laboratory measurements that look at whether an immune response to the food has been generated. And if there is no evidence of an immune response underlying the disease, it's more likely to be immune tolerance.

NNAMDIIt -- I think there's...

FENTON(word?) tolerance.

NNAMDI...a -- I think there's a common perception, Hemant Sharma, that in the U.S., food allergies are on the rise. Is that perception accurate?

SHARMAIt is. It definitely appears that food allergies are increasing in prevalence. For example, a generation ago, you just didn't hear about all of these children, in particular, who had food allergies. And there have been a number of studies that are suggesting that the prevalence, for example, of peanut allergy or any food allergy for that matter has gone up as much as almost 20 percent in about the past decade.

SHARMAOne of the difficulties with the studies is what you just touched on, how do we define a food allergy? And so one of the barriers to accurately finding out how many people have a food allergy is that each study seems to define it slightly differently. But we think that approximately an estimated 12 million Americans have a food allergy and about 3 million of those are children.

NNAMDIAny hypothesis as to why this might be on the rise?

SHARMAThere are hypothesis, but unfortunately we don't have a great handle on which one or ones are correct. One of the hypotheses is called the hygiene hypothesis, for example, which states that we're just too clean of a society and that young babies are not getting exposed to infections as much as, maybe, perhaps, they would a generation ago or in other countries. And then the immune system says, hey, I'm bored. What am I going to do? Let's develop a food allergy.

SHARMAThere's evidence both for and against this hygiene hypothesis. Another theory is that we are delaying the introduction of foods too late. And by avoiding foods until later in childhood, we're leaving the immune system an opportunity to not develop a tolerance to that food, but to instead develop an allergy. Unfortunately, we don't know which theory is the correct one. But there is research looking into that.

NNAMDIMatthew Fenton, the National Institute of Allergy and Infectious Disease has spent several years putting together new guidelines for doctors who treat patients with food allergies. Tell us a little bit about these guidelines and why you decided to issue them.

FENTONWell, this project began back in late 2007 when we were approached by a professional medical society and a patient advocacy group. who came to us and said, we think that there's a strong need for an updated (word?) of clinical practice guidelines in food allergy that bring together the desperate ways that food allergy is defined, diagnosed and managed across a variety of different medical specialties. There have been excellent clinical practice guidelines written in the past, but many of these have been written, for example, for allergists and written by allergists.

FENTONWhat we strove to do in these new guidelines was to create a document that could be used by all clinical practitioners from specialists in urban centers through family practice physicians in rural areas.

NNAMDI800-433-8850 is the number to call or you can go to our website, kojoshow.org, and join the conversation there. It is my understanding that one of the first challenges you face when dealing with food allergies, as you talked earlier, is confirming that a patient has an allergy. How do you test for food allergies? And why -- more importantly, since you mentioned how you can test, blood tests, skin prick tests, why is it sometimes hard to make a definitive diagnosis?

FENTONThis, Kojo, is one of the biggest challenges, I think, that practitioners face, is making the correct diagnoses. And there are a number of tests that can be done to look to see whether someone has a food allergy. For example, you mentioned skin tests. Those are done on the surface of the skin where a little drop of a liquid extract is put on there and then pricked through. And we're looking for a skin response, a hive in the location of contact to tell whether or not that test is positive.

FENTONBlood tests can also be done. And these blood tests are looking for the allergic antibody that the immune system has made specific to a given food. But the problem with tests are that they are not 100 percent accurate and so you can have what are called false-positives. Where a test is coming back positive, but, in fact, when you ask the patient or the parent, do they have symptoms after they eat the food, they say, no. But yet, the test is showing up positive.

FENTONConversely, you can also have false-negatives. And so because of this inaccuracy about the testing, that's why it's so important to listen to what the person says happened after they ate the food. That's perhaps the best way to truly diagnose a food allergy.

NNAMDIYeah, my brother, the sadist, would've loved this one, the oral challenge. When you give the person the suspected food and wait to see if they have an allergic response, right?

FENTONAbsolutely. And we do it in our clinic in the food allergy program at Children's...

NNAMDIThat's not the most desirable route.

FENTON...all the time. Well, you know, if the diagnosis is not clear, if, for example, the history is a little bit uncertain or the testing is conflicting, than that's going to be your definitive answer. Have them eat the food in gradually increasing quantities and then watch and see what happens. We don't recommend doing this at home. We would want to do it in a controlled medical environment where if they do have a severe reaction, we can manage it appropriately.

NNAMDIOn to the telephones. We'll start with Heidi, in Alexandria, Va. Heidi, you're on the air. Go ahead, please.

HEIDIHi, I -- first of all, I love your show, Kojo. I have a daughter who's almost 13 who was diagnosed with a peanut allergy and a number of other allergies that she outgrew when she was probably a year and a half. And because she had, you know, the testing indicating a severe allergy, we did a rash test, just the blood test a couple years back and it indicated that -- still looking at a allergy was hanging on. But she's never had the reaction, except for if someone touches her with a little peanut butter, she'll get a hive. She washes it off, it's all fine.

HEIDIAnd I've often thought that she's getting a little bit older. I know some very small percentage of kids do outgrow this. And I wondered what is the latest thinking on retesting what, you know, if we're not even -- now, I'm hearing that maybe she's got an intolerance and not an allergy. I just wonder how that works and I'll take the answer off the air.

NNAMDIThank you for your call. I'll ask both of our specialists here. Matthew Fenton, first.

FENTONSure. I think the physician -- you should have the tools available to get a pretty strong indication of whether this is a food intolerance as opposed to a true food allergy. The presence of antibodies against the peanut, for example, which would also generate a positive skin prick test, is a pretty good sign that we're dealing with an allergy. Now, unlike milk or egg, peanut allergy does not tend to be outgrown. Only about 20 percent of people who develop a peanut allergy ever outgrow it in their life and the reverse is roughly true for milk and egg.

FENTONSo we -- in the clinical practice guidelines that were recently released, we do advocate routine testing in situations where there's an expectation the patient may outgrow the food or a period of time has passed with no unexpected reactions. But also we don't advocate doing it so frequently the patient and the family is constantly panicking.

NNAMDICare to answer the same question, Dr. Sharma?

SHARMAYeah. So in our clinical practice, as the guidelines recommend, we do routinely at some interval specific to the family, retest to see what exactly that peanut specific IGE level has done, whether it's gone up, whether it stayed the same, whether it's come down. And at some point, if it's come down enough, below a certain threshold where we think there's a good enough chance of passing a food challenge, we might then do an oral food challenge to, for example, peanut in our clinic.

NNAMDIA lot of people who have severe allergies often carry what's known as an EpiPen with them in case they accidentally eat the food they're allergic to. How common are these severe responses to food allergy?

SHARMASo the -- there is some difficulty in identifying the specific number of severe allergic reactions that occur each year. But we do know that every child who has a diagnosed food allergy due to IGE, which is the allergic antibody, it's theoretically at risk for having one of these severe life threatening reactions. The symptoms can include problems with hives, swelling, problems breathing, swelling of the throat, gastrointestinal symptoms like vomiting and diarrhea and can even cause a drop in blood pressure.

SHARMAAnd so the medication that you mentioned, Kojo, that EpiPen or Epinephrine is an injectable medicine that can reverse these life threatening symptoms. And it's absolutely important for all of our patients to carry this medicine with them at all times because you can never predict when one of these life threatening reactions may occur.

NNAMDIDr. Fenton, how common is it for someone with a mild reaction to develop a more serious response?

FENTONI think one of the scariest aspects of food allergy is that a past history of mild responses is not necessarily an indicator that future responses will be equally mild. So that's what makes it very difficult to precisely determine who should or shouldn't carry Epinephrine with them because of that uncertainty.

NNAMDIOn to Tanya in Clarksburg, Md. Tanya, your turn.

TANYAThank you so much for having me on. I really appreciate it. I'm just wondering what your panelists think about the idea of alternative medicine. I have a friend whose daughter had a severe peanut allergy reaction and was taken to the hospital, you know, all of that, and ended up going to an allergist, testing positive, saying, you know, you have to avoid peanuts and ended up being treated by an alternative medicine doctor using homeopathic remedies and, I believe, acupuncture as well.

TANYAAnd lo and behold, she's no longer allergic to peanuts. She's had her blood retested and the allergist seemed rather amazed by it. I, myself, don't have food allergies, but I was able to treat a severe cat allergy in the same way. And I'm just wondering what your panelists think about the idea of alternative medicine for something like this.

NNAMDIFirst...

TANYAAnd I can take my comments off the air.

NNAMDIOkay. Here's Dr. Sharma.

SHARMASo this is a great question and one that I think we need to study more. There has been some interest in the use of, for example, Chinese herbal medicine in the treatment of food allergy and that's currently being studied by the group up at Mount Sinai in New York. But the use of acupuncture, homeopathic medicine hasn't been extensively studied for the treatment of food allergies so we don't have a great handle on its effectiveness or if it is effective how it actually works.

SHARMASo what I usually recommend to patients is that if they're interested in pursuing one of these alternative medicine therapies to only engage in things which at the minimum don't appear to be dangerous. I can't give them any sure statistics on what the chances are that it would help, but if it doesn't seem like it's going to hurt, they're certainly welcome to do that. But unfortunately, we just don't have great research yet on the utility of these alternative modalities.

NNAMDIDr. Fenton?

FENTONWell, I wanted to point out first that at the current time there are no FDA approved treatments for food allergy. The epinephrine we discussed earlier is for use in managing severe reactions and other medications, such as antihistamines, serve the same purpose, to manage the reactions. The NIH is funding a number of clinical trials that are exploring what we think is a potentially powerful new therapy, which is generally known as immunotherapy, the idea of giving the allergen in some form to the patient in a graded dose over a particular period of time and by any one of a number of different routes, orally, under the tongue, on the skin or even through injection and then reprogramming the immune system to tolerate that allergen so that after a particular time of treatment, their immune system no longer sees it, in a sense, as a foreign invader, but knows to tolerate it.

NNAMDIGot to take a short break. When we come back, we will continue this Food Wednesday conversation on food allergies. If you're calling and the lines are busy, then go to our website, ask a question there. It's kojoshow dot or you can send us a tweet at kojoshow, shoot an e-mail to kojowamu.org. I'm Kojo Nnamdi.

NNAMDIIt's a Food Wednesday conversation, but we're discussing food allergies with Dr. Matthew Fenton, chief of the asthma, allergy and inflammation branch at the National Institute of Allergy and Infectious Diseases. He's one of the primary authors of "New Clinical Guidelines for Doctors Who Treat Patients With Food Allergies," and Dr. Hemant Sharma, director of the food allergy program at Children's National Medical Center. We got this e-mail from Lawrence. I decided to go to it so I could get the pronunciation issues out of the way.

NNAMDILawrence says, "I was recently diagnosed with eosinophillic esophagitis, which is an inflammation of the esophagus that is believed to be related to food allergy. I'm going to get tested in two weeks for various food allergies. I was under the impression that allergists are getting more familiar with this problem and wanted to know what the guests say about it. First, you pronounce it five times, Dr. Sharma.

SHARMAThat was an excellent job pronouncing it, Kojo.

NNAMDIThank you.

SHARMAAnd we were just joking, Dr. Fenton and I, that we abbreviate this condition, EE, so that we don't have to pronounce it every single time.

NNAMDIThank you.

SHARMABut there are a number of more patients being diagnosed with this inflammation in the esophagus with a particular kind of white blood cell, that's the allergic white blood cell called the eosinophil. And there is thought and evidence that this inflammation is triggered, at least in part, by foods. And so it's a form of food allergy that is more delayed in its presentation. So you would not have esophageal symptoms immediately after eating the food, but the food, over time, with chronic ingestion, would lead to inflammation of the esophagus, which can cause symptoms, including abdominal pain, vomiting, problems with swallowing and in some cases, even food getting stuck in the esophagus.

SHARMASo we're learning more and more about this condition and we do -- and the guidelines do support an assessment for food allergen triggers of this esophagitis in patients who present. And that assessment is done often with a combination of testing modalities, using some blood tests as well as skin tests.

NNAMDIDr. Fenton, is there any understanding of why a person might develop an allergy to a food after years of eating it? Why does the body all of a sudden seem to trigger this response?

FENTONWell, it's a great question, Kojo. And Dr. Sharma mentioned at the beginning of the hour that the hygiene hypothesis is one of those concepts that's been foot forward for why we see an increasing number of allergies. But in addition to whether we are exposed to a cleaner versus a less clean environment in our society, there are a number of factors that also have a very strong role in determining the risk to food allergy. Family history and genetics is one, many of these diseases often track in families. Early exposures to pathogens, respiratory viruses within the first year or two of life are critical. There's some thought that even the diet of the mother while she's pregnant can be very important in that we see newborn babies with evidence of antibodies against food in their bloodstream.

FENTONBut also turns out that one of the factors that may play an important role are the bacteria that live within our own gastrointestinal tract. These bacteria can change, they can influence allergic responses. They can even be affected by diet. So as people move throughout life to new environments, move from one city to the next or one country to the next, they're exposed to new allergens, their new foods, their -- the microbes in their gut change very quickly. Even bringing a pet into the household is enough to change the microbes that live in your gut. All of these can play a role in triggering an allergy, even in adults.

NNAMDIAnd I guess Jonas in Davidsonville, Md. wants to talk about the reverse of that. Jonas, you're on the air. Go ahead, please.

JONASHi. I am 14 and for a long time I've had some -- like, a lot of allergies. Recently, I outgrew peanuts and soy, but I've got a wheat and gluten allergy, which I carry an EpiPen for 'cause I go into anaphylactic shock if I ingest it. And I was wondering what the chances are that I'd eventually outgrow it because it's really, really, really annoying.

NNAMDIDr. Sharma, I know I've seem to outgrow some intolerances but is it possible to outgrow allergies, so to speak?

SHARMAGreat question. And first of all, I'm glad that you outgrew the peanut and the soy allergies. It is absolutely possible to outgrow food allergies. The likelihood of outgrowing a food allergy depends somewhat on the specific food. And so as Dr. Fenton alluded to before, peanut allergy is one of the harder food allergies to outgrow. Maybe only about 20 percent of people with a peanut allergy will outgrow it over time, whereas some other foods, like milk, eggs, soy and even wheat, the numbers are much more favorable, up to 80, maybe even 90 percent of people who have those allergies will outgrow them. We use to think that you -- if you were going to outgrow your allergy, you would outgrow it in early childhood. There's some recent data that suggests that you can even outgrow your food allergies into later adolescence or early adulthood.

SHARMAThe way to find that out, again, is to follow the test results, specifically the blood test result to see what the level is doing over time. And if it is trending downward that may be an indication that the food allergy is being outgrown.

NNAMDIJonas, does that answer your question?

JONASYeah. Wow. That's great news. Thanks so much.

NNAMDIJonas, thank you very much for your call. A number of calls and e-mails about peanut allergies. I'll start with one from Terry who says, "My daughter has a severe peanut allergy and my husband has been working with Dr. Robert Wood at John's Hopkins to further research in the sublingual immunotherapy area. Basically, giving the affected person a tiny amount of, say, peanut powder, then working up to a whole peanut. Because drug companies will not make money off of this process, we're looking at a delivery mechanism rather than a drug. It is difficult to secure funding for this research. Can you discuss your thoughts on this future potential cure and thoughts on funding?" Matthew Fenton?

FENTONWell, it's certainly a question that I have to deal with every day and the NIH, which is the major funding source for food allergy research in this country, is very dedicated to providing research funding to develop new treatments. So the caller is referring to a type of immunotherapy similar to what I mentioned earlier in that you are giving a small amount of this material, building it up over time and developing an immune tolerance to this. These are the types of studies, as controlled clinical trials, that we support through NIH funding. We have a large number of similar trials, including trials that are underway by Dr. Wood and others to look at this type of treatment for peanut, as well as milk, and egg and other allergies.

FENTONSo I think we're putting a lot of money into this. Since 2003, the amount of funding by the NIH for food allergy research has gone up about 16 fold. So there's been a large interest in this from the NIH, from Congress and we're doing our best to see the dollars flow into this area.

NNAMDIAre food allergies more common in children than they are in adults?

FENTONThey are overall and this is probably the -- due to the high -- relatively high rate of milk and egg allergies in these children that they think tend to outgrow.

NNAMDIThis we got from Stacy in D.C. "One year, our elementary school nurse banned all nut products because there was a girl in the class with a peanut allergy. I thought that it was extreme. Other schools allow children to eat nut products at a designated table and ensure that it's cleaned later. The child's mother insisted that she could have a severe reaction from smelling peanut butter, but I thought that that idea had been discredited and that a severe peanut allergy only occurs from touching the oil, and then your nose, mouth, et cetera, or breathing in peanut dust, which is not an issue with peanut butter. What is the current recommendation for classrooms?" Do you know, Dr. Sharma?

SHARMAAnother great question. And I think one that many families with a child with peanut allergy have to face as they decide what policy to implement in their school. What we know, in terms of the cause of reactions, is that injection of the food, as well as contact with the food on the skin, are by far the most common routes of exposure that will cause a reaction. Inhalation is a very rare route by which someone can have a food allergic reaction. And as Stacy had mentioned, that usually would occur in an environment where there's dust or somehow aerosolization of the food allergen into the air in an enclosed space that doesn't have great ventilation.

SHARMASo in terms of schools and what policies they choose to implement, it's a tough issue and I think for young children, given that I am a pediatric allergist, young children share food. They touch each other. They -- they're not shy about taking something from their friend at the lunch table and so...

NNAMDIAnd eating it before the friend notices, usually.

SHARMAExactly. And, you know, and at that young age, I think it is entirely reasonable to suggest that there be peanut-free policies, for example, in the lunchroom, a peanut-free table. Once children get older, oftentimes those sorts of policies can do more harm than good. They can be very isolating for the child who has a food allergy to have to sit separately from their friends and peers. And so I think that every family comes to some sense of what they're comfortable with. But as much as possible, we try to allay anxieties about the smell of peanut butter causing a reaction because in the long run, it is more helpful for the child to adjust to having this peanut allergy as they age.

NNAMDIDr. Fenton?

FENTONJust wanted to point out that on January 4, the president signed a new law. The Food Allergy and Anaphylaxis Management Act was signed and one of the major goals of this is to create guidelines for food allergy management and treatment of anaphylaxis in schools. So we're well on our way to developing guidelines that will be disseminated to schools and the government will work with those schools to help to implement these policies.

NNAMDIMassachusetts has a new law that requires restaurants to take steps to cut down on exposure to potential allergens. From a public policy perspective, should we be requiring restaurants to disclose allergens or take other precautions to protect people with food allergies?

FENTONWell, I think if you've ever gone out to dinner with a friend who has a food allergy, you recognize the difficulties here. I myself was at a restaurant a couple of weeks ago where the second question out of the waiter's mouth after how are you this evening, was do you have any food allergies? And I thought that was an excellent question. So wait staff need to be trained, the cooks, the chefs, the management. These questions are appropriate and there's never a downside to asking them.

NNAMDICare to comment on that, Dr. Sharma?

SHARMAI agree entirely. I think that for families who are dealing with a food allergy, restaurants pose one of the greatest difficulties because you have no idea what's happened to the food before it arrives at your table. And there's this phenomenon called cross-contamination or cross-contact where even if the food, for example, doesn't contain peanut, if you're peanut allergic, if the same utensil or the same countertop was used to prepare your food and it happened to touch peanut in some way, that could have enough of an exposure to cause a reaction.

NNAMDIBut what about airlines that serve peanuts or schools that allow kids to bring in birthday cupcakes? How far do we go, as a society, to try to protect people with food allergies?

FENTONI think that there are certain things that obviously families have to take into their own control and take autonomy over. For example, with airline travel, we usually recommend the families to make sure that they clean the area, even if it is a flight that's serving peanuts, that seat that you're child will be sitting in or that you will be sitting in, clean the tray table. Make sure that there are no peanuts sitting in your seat left over from the prior passenger. Certainly some airlines are adopting peanut-free flights, which is great if they're willing to do that. But there are measures that families and individuals with food allergy can take to stay safe, even if you cannot completely get rid of the allergen.

FENTONAnd I should point out, peanut is just one of many food allergies and one common myth is that peanut allergy is the most common food allergy and it actually isn't. In young children, milk -- cow's milk allergy is the most common and in adults, it's shellfish. We focus so many of our efforts on peanut, but from a practical standpoint, you can't remove all of these foods from public environments. It's just not possible.

NNAMDIGlad you mentioned milk because that's what Rebecca in Virginia wants to talk about. Rebecca, you're on the air. Go ahead, please.

REBECCAHi. Thanks for taking my call. My son has a -- many different allergies, including milk, which was first discovered when he tried a milk-based baby formula when he was about six months old and ended up in the hospital and -- in anaphylaxis. And since then, it was very difficult to find a baby food that actually is milk-free. It's astounding, most of the baby food on the market tends to include whey, I think, as a way to increase the protein content, but then, of course, it's got the milk product. So I'd like to hear some comments about maybe getting some baby food that's more appropriate, given that, you know, as the guest just said, milk allergies are the most prominent among children. Thank you.

NNAMDIDr. Fenton, let's start with you.

FENTONWell, let me refer to the food allergy guidelines for my answer to this question.

NNAMDIAnd by the way, we have links to those food allergy guidelines at our website, kojoshow.org.

FENTONGreat. The recommendations we make in the guidelines is that for newborns that the mother breastfeed wherever possible up to the first six months of life, and exclusive breastfeed where possible. If the child has a problem with a milk-based formula, there are different types of formulas known as hydrolyzed formulas, and even more fundamentally what we call elemental formulas that can be used in severe cases where there are no milk products at all, but the nutrients are built up and assembled from scratch to make a non-allergenic or hypoallergenic formula.

NNAMDIBroader question for you, Dr. Sharma. Many nursing mothers have been told to eliminate certain foods from their diets to protect allergic infants from exposure to those foods. Is this a useful practice? What do you think?

SHARMASo this is an area that is one of somewhat uncertainty, and many of the -- many of our professional organizations have modified their policy about this recently. In the guidelines, which Dr. Fenton organized, the statement is made that there aren't -- this is not evidence that avoidance of foods either during pregnancy or breastfeeding is going to be protective or preventive in terms of that child developing a food allergy.

SHARMAAnd that's where we are right now. And so for families in which there's a child who may be at heightened risk for developing a food allergy, either because there's another child in the family, or another family member who has food allergy already, there are not currently recommendations to say that that mom should avoid that given food allergy under any of the most common food allergens.

NNAMDIRebecca, thank you very much for your call. Was your question appropriately answered?

REBECCAYeah. I'm just also curious beyond the formula, as the child gets older, all the baby food on the market, most of it has milk products too.

SHARMAYeah. That's a great point and with regard to that, from a practical standpoint, a lot of families who have babies with milk allergy end up making their own baby food, which is not easy as the parent of the 13-month old. My wife and I tried to do that for a period of time, and it quickly becomes a difficult task. But you're exactly right, that with the increased awareness of food allergy, we really need to get food manufacturers more familiar with the common food allergens and practices that would help make it easier for families that need to avoid common foods like milk.

NNAMDIGot to take a short break. Rebecca, thank you very much for your call. If you too would like to call, the number is 800-433-8850 to join this conversation about food allergies. Or you can send us an e-mail to kojo@wamu.org. I'm Kojo Nnamdi.

NNAMDIWe're discussing food allergies with Dr. Hemant Sharma, director of the food allergy program at Children's National Medical Center, and Dr. Matthew Fenton, chief of the Asthma, Allergy and Inflammation Branch at the National Institute of Allergy and Infectious Diseases. He's one of the primary authors of "New Clinical Guidelines for Doctors Who Treat Patients With Food Allergies." You can find a link to those guidelines at our website, kojoshow.org.

NNAMDIMany parents are told to hold off on introducing food with nuts, shellfish, and other allergens to their babies, but a new report in the British Medical Journal suggests this may actually be causing more allergies, rather than preventing them. What do you think? First you, Dr. Fenton.

FENTONWell, the story that comes to mind is one that we learned about Israeli children, and that there's a very commonly consumed peanut snack called bamba. In Israel, the saying goes that a child's first words are mama and bamba. And so with this widespread use and very early consumption of this peanut product, it's interesting to note that rates of peanut allergy in Israel are far lower than they are in other developed countries.

FENTONAnd this concept was taken forward by Dr. Gideon Lack and his colleagues in London to perform a large and very interesting peanut allergy prevention trial where we're comparing -- and we're funding this through the National Institute of Allergy and Infectious Diseases, and in study we're comparing children who are on a continual peanut consumption, bamba or other peanut snacks, from very early points in life, and comparing that to children who have been put under peanut avoidance, and the concept is to look several years later by age five or so, and ask whether or not there's a difference in the development or the rate of peanut allergy in this children.

NNAMDIYeah. Because looking at it anecdotally, Dr. Sharma, it certainly appears as if you give the child those things at an earlier age, there is likely to be a greater resistance to the allergy than if you don't.

SHARMAAbsolutely. And one of the theories is that the longer you wait to introduce a food by mouth, the more opportunity there is for that food to contact the child's immune system through the skin and, for example, children who have eczema, their skin is an imperfect barrier, and so many of them go on to develop several food allergies, and one of the potential explanations could be that they had exposure through the skin before they had exposure by mouth those foods.

NNAMDINo, Andrew. That doesn't mean you start your children drinking beer earlier. Rachel in Silver Spring, Md., you're on the air. Go ahead, please.

RACHELGood afternoon. I have a very simple practical question, and a larger theoretical question. The practical question is can you discuss the safe disposal methods for used or unused by expired EpiPens, and the larger question is, is there any solid scientific evidence to link food allergies or intolerances with a diagnosis somewhere on the autism spectrum, particularly Asperger's Syndrome or high-functioning autism.

NNAMDIFirst you, Dr. Sharma.

SHARMASo I'll attack the practical question first, because I think it might be easier to answer that one. The injectible epinephrine, and we've been calling it the EpiPen, although that's only one name brand for injectible epinephrine, is a product that needs to be disposed of in a Sharps container, which are usually only found at medical facilities. And so at the point that it's expired, which is usually at the end of a year, that should be brought to either your doctor's office, or to a hospital for them to dispose of it safely.

SHARMAThe other question about any potential association between food allergy and autism spectrum disorders is an interesting one, and there are a number of my patients who have children who have autism spectrum disorders, and will vouch that the child improved after removal of certain foods from their diet, for example, casein or gluten. And although there isn't any firm evidence for this, there do appear to be anecdotal reports of it, mostly from parents.

SHARMAAnd so at this point in time, if families are interested in doing that, I usually advise them of the nutritional implications just to make sure that the child will be nutritionally replete, but unfortunately, there's no compelling evidence as of date to suggest that there is going to be a dramatic improvement after food allergen avoidance.

NNAMDIRachel, thank you very much for your call.

RACHELThank you very much. Bye-bye.

NNAMDIWe got a tweet from the allergy mama who says, "How are the new clinical guidelines integrated and shared with medical staff, nurses, and within our public education system?" Dr. Fenton?

FENTONWell, rolling out the guidelines to the clinical communities is an ongoing process. It begins with the publication of the guidelines in journals that are widely read by the clinical and clinical research communities. The guidelines have been published so far in four different journals. They're available free through the Internet, through PubMed, which is an NIH-based resource for scientific literature. It's also available free through the Journal of Allergy and Clinical Immunology where the guidelines were first published.

FENTONSo these -- and it's also available through the NIAID website. We've, in addition to publications, we've also been giving a number of presentations at large national meetings of clinical societies from different specialties, dermatologist, gastroenterologists, pulmonologists and such. And also radio shows like this and the media. We've had a lot of great coverage over the past couple of months, and all of these factors are important in making sure that dissemination could be done as broadly as possible.

NNAMDIHere not is Amanda in Bethesda, Md. Hi Amanda.

AMANDAHi Kojo. Thanks so much for having me on the show.

NNAMDIYou're welcome.

AMANDAI -- I think that maybe your previous caller might have addressed some of the -- one of the questions that I had. I was -- I have a four-year-old son who has a history of asthma, also an egg allergy that he outgrew, and a positive test for peanut allergy though he's never reacted. He also had a recent intolerance test, and tested positive for dairy intolerance or casein intolerance, but not for gluten. We are looking at how that might affect -- the intolerances might affect his behavior, and your previous caller had asked about the autism spectrum.

AMANDAHe is not on that spectrum, but we were interested in some of the behavior, how that might be affected by this kind of grouping of connected things that he had been diagnosed with in the past.

NNAMDIEffect on -- effect on behavior, Dr. Sharma?

SHARMASo to review a little bit about food intolerance, just to make sure that I understand what testing has been done, it's not something that involves the immune system at all, and perhaps the best example of intolerance is lactose intolerance, which a lot of us know someone who has that. Your body in that case can't digest the sugar, lactose, and as a result, symptoms such as abdominal cramping or diarrhea can develop.

SHARMAIn a food intolerance, there certainly might be implications on behavior, and so for example, if a child is chronically bothered by gastrointestinal complaints, perhaps that could affect behavior. We've also noticed that in some children who have more chronic forms of food allergy, that involve the gastrointestinal tract, there are improvements in their behavior once you find the food that is triggering their symptoms, and it's removed from their diet.

SHARMASo there are potential implications and connections between food allergens and behavior. I hope that I've answered the question appropriately.

AMANDANo. That's great, thank you so much. I know that there is a lot of, you know, as you said before, anecdotal, you know, accounts of parents trying this, and, you know, nothing hard and fast.

NNAMDIAnd...

AMANDABut it's great to hear your opinion about it.

NNAMDIAmanda, thank you for your call. And you should all know that next week on Food Wednesday, we'll be doing a show about making your own baby food. So you may want to join us then. We got this e-mail from Doreen in Alexandria, Va. "I have read that food allergies can change dramatically at puberty. My son has not had any reaction in two years. Do I need to worry more as he approaches puberty?" Dr. Fenton?

FENTONWell, I think this goes back to the point we were discussing earlier. If there is a history of reactions and especially severe reactions, parents and the child will need to know if this is an ongoing clinical condition and a concern. And especially for children who are reaching their teenage years where they're out of the house on their own more frequently, and they're not under the watchful eye of parents, and you never know when they're going to be invited somewhere to grab a quick bit of food, and what dangers that might put them in.

FENTONSo I think that routine testing is important if there's a strong history of food allergy because of the potential that someone has outgrown that food, and that can be shown through both their ability to safely eat the food, and as Dr. Sharma indicated earlier, changes in their blood tests, lowered levels of the IGE antibody for example. These are all good signs that tolerance may have occurred and that it's now going to be safe for that person to start consuming the food.

NNAMDIAnd Doreen, there are some other things you might have to worry about more as he approaches puberty, but this is not the time to discuss those. Here's Twi in Springfield, Va. Twi, you're on the air. Go ahead, please.

TWIYes, hi. I have a five-year-old daughter who was in anaphylaxis when she was about nine months old. She had a reaction to some milk-based formula. But anyways, basically she's been tested annually since then, and she's had a blood test once, but most of them have been skin tests. And I've read that blood tests are more reliable in some cases, but then I brought it up to her last year -- her allergist last year, and I asked her if she should have a blood test instead of a skin test, and she said in her opinion, skin tests are more reliable in some instances, and she didn't think that we should need a blood test.

TWISo I guess that's the question is, which is more reliable for...

NNAMDIDr. Sharma?

SHARMAGreat question. And, you know, the difference between the blood and the skin test somewhat is in the kind of information they give you. So a skin test will create a wheel if it's positive, a little hive on the skin. A blood test will actually give you a number, somewhere between 0.1 and 100. And that -- that number oftentimes is helpful in terms of predicting the likelihood of whether a child will pass an oral food challenge.

SHARMAAnd so reassessment of food allergy with a blood test can be very informative. The size of the hive on skin tests can sometimes give you similar information, but oftentimes the blood test is what is followed periodically.

NNAMDIIt seems -- what -- well, no. I'll get to my final question because we're running out of time. What's the future of diagnosing food allergies, Dr. Fenton? Will we get to a point where the process of diagnosing these allergies will become a bit more definitive?

FENTONWell, right now, even with the oral food challenge, we have a tool at hand that can give a very reliable diagnosis. And when this is paired with good family history and even data from the skin test and the skin prick test, we have a lot of tools that are currently available. Where we really are lacking tools are in ones that help us predict whether a reaction will be severe or not. Whether a person will be more prone to just simple hives or full blown anaphylaxis.

FENTONAnd that difference is much more subtle, and it may depend on a number of different factors measuring various markers in the immune system, but also looking at other tests that measure genetic risk or looking at the composition of microbes that live in the gut, assessing the diet, combining a lot of different data that allow you to develop an overall risk pattern. We talked before about eczema or atopic dermatitis where there's a somewhat damaged or leaky skin barrier.

FENTONAll of these things can affect the risk factor. So I think there's diagnosis which we can do not, but more importantly, the assessment of risk which still needs a lot more work.

NNAMDII'm afraid that's all the time we have. Dr. Matthew Fenton is chief of the asthma, allergy, and inflammation branch at the National Institute of Allergy and Infectious Diseases. Dr. Fenton, thank you for joining us.

FENTONThank you.

NNAMDIDr. Fenton is one of the primary authors of "New Clinical Guidelines For Doctors Who Treat Patients With Food Allergies." You can find a link to those guidelines at our website, kojoshow.org. Dr. Hemant Sharma is director of the food allergy program at Children's National Medical Center. Thank you for joining us.

SHARMAThank you, Kojo.

NNAMDIAnd thank you all for listening. I'm Kojo Nnamdi.