How To Handle Hay Fever The birds are singing, the sun is shining — and for many that means sniffling, sneezing and suffering. Can science shed any light on how to manage seasonal allergies? Allergy experts sort fact from folklore, explain the science behind pollen counts and suggest remedies.

How To Handle Hay Fever

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You're listening to SCIENCE FRIDAY from NPR News. I'm Ira Flatow. Years ago, when I was a teenager, I used to be afraid to go sit out on the lawn or go out on a picnic or on the grass with my friends because I knew I would have to pay for it later in the day, literally.

After sitting out on the grass I'd wind up with a terrible wheeze, a bit of asthma later that night. I even took allergy shots to combat my allergic reactions to grasses, pollens and weeds, as it was diagnosed, but they didn't really seem to do much good.

Then, you know, something weird happened. In my late 20s, as if by magic, my allergies started to go away. I mean, they started to disappear on their own. They lessened each year until I - today I rarely experience any kind of allergy, allergic reaction.

But I bring this up now because we're in the teeth of the spring allergy season, and I know this because I hear from so many of my friends and colleagues, telling me how terrible they are suffering. They've got the stuffed sinuses, the runny nose, the itchy eyes, even in the desert of Arizona.

So we thought we'd talk today about allergies and see if we can bring up, bring us all up to date on the many questions, the many myths circulating among us, like - you know, how - should I take bee pollen? Things like that.

We'll try to get into all of these things and we'll talk about why allergies may suddenly appear, may suddenly disappear, like in my case. Why do some allergy drugs lose their effects after a year? Lots of questions for my guests.

If you'd like to join in and ask anything you'd like to know about allergies, our number is 1-800-989-8255, 1-800-989-TALK. Also you can Twitter us. We'll take your tweets @scifri, @-S-C-I-F-R-I, and also in Second Life. Folks are gathered around there, and we'd be happy to hear from you.

Let me introduce my guests. Dr. Calman Prussin is chief of the Lymphocyte Biology Section of the Laboratory of Allergic Diseases, and he's at the National Institutes of Allergy and Infectious Diseases, and that's part of NIH in Bethesda; you knew that. He joins us from WBEZ in Chicago. Welcome to SCIENCE FRIDAY, Dr. Prussin.

Dr. CALMAN PRUSSIN (National Institutes of Health): Great to be here, Ira.

FLATOW: Thank you. Dr. Michael Kaliner is a professor of medicine at George Washington University School of Medicine. He's also medical director of the Institute for Allergy - for Asthma and Allergy in Chevy Chase, and he has consulted and lectured for a number of different pharmaceutical companies. He joins us by phone. Welcome to SCIENCE FRIDAY.

Dr. MICHAEL KALINER (George Washington University School of Medicine): Hi, Ira.

FLATOW: Thank you for being with us today. Let me ask you first, Dr. Prussin, is this an unusual allergy season, or you know, why - does it strike you that way?

Dr. PRUSSIN: Well, every allergy season is an unusual one if you have allergies, in a sense, but they do - some are worse than others because of the weather, whether it's, you know, a milder winter - you can get more germination of various flowers, increased pollen. If it's very windy, you'll have higher pollen levels. So every season is unique.

I haven't perceived it in my own experience in terms of what I've heard, but different localities, different parts of the country, may experience it different as well.

FLATOW: Dr. Kaliner, your experience this year?

Dr. KALINER: Well, as Cal said, every year is terrible.

(Soundbite of laughter)

Dr. KALINER: What I actually tell patients is that this is the worst year ever.

FLATOW: Every year.

Dr. KALINER: Every year. But in reality, this year, which started early-ish, because we had a fairly mild winter, has not been unusual at all in the pollen counts, and so patients just forget from year to year how terrible it is.

FLATOW: And you can actually go online and see the pollen counts in different cities around the country.

Dr. KALINER: That's right.

FLATOW: And what do they tell you? I mean, are they really useful, or are they just a scorecard for keeping score?

Dr. KALINER: Well, they tell you what's in the air so that, for example, I'll just give you our own level of ignorance. When we first set up our practice, we did not recognize that an evergreen called cedar was in the Washington, D.C. area. We just didn't know it was here. And when we started looking at pollen counts, lo and behold, in February and March, patients were complaining of symptoms, and the only thing in the air, the absolutely only thing in the air, was red cedar.

And so we started skin-testing the red cedar, and lo and behold, that's what caused their symptoms. So it allowed us to identify an important allergen of which we were unaware.

FLATOW: We're going to have a little bit later in the program, Dr. Jay Portnoy is going to come on to talk about the pollen counts and how to deal with them.

But let's talk about what happens in your body. When you're allergic to something, Dr. Kaliner, what happens when pollen enters an allergy sufferer's nose? Walk us through the reaction that goes on there.

Dr. KALINER: Well, a pollen grain is the male gamete. It's the sperm equivalent from a plant. So it's out looking for a female plant, like all of us guys do, and when it gets into the nose, it honestly can't distinguish the nose from a female plant.

And so on the surface of the pollen grain are water-soluble enzymes that come off a surface and act as if it was trying to open up the channel for which the gamete can get to the female plant and impregnate it, and those water-soluble enzymes are largely the allergens to which we are allergic.

So you know, what happens is the plant is, by mistake, on our nose and gets us exposed to that allergen, and you have to be then genetically predisposed to recognize the allergen. So only about 40 percent of the people in the United States are genetically capable of seeing that allergen and then responding to it by making an immune response.

The other 60 percent don't even see it. They don't recognize it as anything, and it's totally invisible, but for those of us like you and I, and Cal, we see the pollen grain enzyme, and we make a specific immune response to it, and that involves the creation of a new antibody called IGE.

That IGE takes about, oh, anywhere from two to 10 years to get to the level where you become sensitized. So you have to be exposed and exposed and exposed, and then you make enough IGE antibody to become sensitive to the pollen, and then the next time you're exposed to it, that antibody is sitting on the surface of a cell that contains histamine, and the histamine is released from the cell and causes the allergic reaction, which makes us sneeze, wheeze and itch.

FLATOW: So that's why it could take years to develop an allergy?

Dr. KALINER: That's right. So people come and they say, I can't be allergic to my dog, I've had this dog for five years. And we say, that's perfect.

(Soundbite of laughter)

FLATOW: That's how long it took.

Dr. KALINER: Right.

FLATOW: Dr. Prussin, what is the immune system trying to do in these cases?

Dr. PRUSSIN: Well, to the best of our - the types of immune responses you make to allergens are very similar to the immune responses we make to parasites, to worm parasites, and to our best understanding it's essentially a mistake that the immune system is making.

These pollens, animal danders, they're not dangerous. They're not going to hurt us. So our immune system should ignore them, but it's somehow miscued, and instead it's making what we call a TH2 type of immune response, this IGE immune response, thinking it's attacking a parasite, possibly.

FLATOW: Well, my question about all of this is something I've been wondering for years. If our bodies are used to seeing these over the years, why don't they get better at fighting them off, or are they fighting them off, and that's the problem?

Dr. PRUSSIN: You're exactly right. So they think they're fighting them off by making, every year, often a better immune response, and so in the first few - let's say somebody - for example, we have post-doctoral students from other countries. They come to the United States without any allergies, and then after a year or two they start having symptoms, and every year - the first year it's not so bad. The next year it's a little worse.

So as your immune system builds up more immunity, think of like a vaccine. You get a few - every time you get it, you get more and more immunity; you get a better immune response and more inflammation, more itching, more wheezing and things like that.

FLATOW: And that's what happens with all kinds of allergens, including bee stings, things like that?

Dr. PRUSSIN: Well, to some degree, but then if you get enough of it, sometimes you actually circumvent those mechanisms, and you get, for example with bee stings, tolerance.

So beekeepers typically are not allergic, and they actually have a specific type of immune response, which gives them tolerance so that they don't have anaphylaxes, sort of a whole-body allergic reaction to the bee sting.

FLATOW: I'm just thinking, you know, it's different from vaccination, where you give us a little bit of, you know, a weakened form of, let's say, a polio virus, or a dead form, and that gives us an immunity. The same thing is not happening here.

Dr. PRUSSIN: That's the treatment, Ira. That's what allergy shots are.

FLATOW: Yeah. I took allergy shots for many years, and I don't think they did anything. Explain to me why I grew out of it, so to speak.

Dr. PRUSSIN: You were lucky.

FLATOW: I was lucky.

(Soundbite of laughter)

Dr. PRUSSIN: It's good genes, Ira.

FLATOW: All right. I'll take that as a good answer. 1-800-989-8255. Let's go to the phones, to Pete from Flagstaff. Hi, Pete.

PETE (Caller): Hi, how you doing?

FLATOW: Hi there.

PETE: I have a question for the doctor. I want to see what his opinion was on neti pots for flushing the nasal cavity of any pollens or allergens that might be trapped up in there.

FLATOW: Yeah, using the saline solution, right?

PETE: Yeah, sodium bicarbonate I think they use in that.

FLATOW: Yeah, does that work, doctors?

Dr. KALINER: Well, it's great, and we have - I would say that I put 100 percent of my patients on some sort of a nasal-washing system, sometimes a neti pot, sometimes just the spray and sometimes something we call sinus rinse, which is where they irrigate the sinuses. But I think that many of the people come back and say that the neti pot is more effective than anything else we use. and so my bottom line is to get patients better, and if that works, I'm happy. It's great stuff.

FLATOW: Do the over…

Dr. PRUSSIN: I would…

FLATOW: Oh, go ahead. I'm sorry.

Dr. PRUSSIN: I would agree with that. The one problem is about half of patients just don't like sticking things into their nose so that's the downside of that. But I think it's effective and for a lot of mild symptoms works well.

FLATOW: Are over-the-counter drugs as good, you know, antihistamines, as stuff that you get by prescription?

Dr. KALINER: Remember every over-the-counter drug was a prescription product and had to prove itself safe and effective before they let it go over-the-counter. And so today's over-the-counter drugs were yesterday's prescription drugs. And the answer is yes. So, you know, what we have available over-the-counter if it works for the patients - Claritin, Zyrtec and all the, you know, we've got 20 older antihistamines that are very inexpensive and still quite good, are fine. We have prescription products that have, maybe some advantages but the bottom line is that antihistamines are antihistamines.

(Soundbite of laughter)

FLATOW: And that's that blast process in the process we talked about -the histamine being released.

Dr. KALINER: Histamine is one of many mediators and Cal can talk about that because that's a part of this research. But there're many other chemicals released in addition to histamine that cause the intense reaction that we call allergy.

FLATOW: Cal, you want to describe that?

Dr. PRUSSIN: Well there's different parts of the immune system and so one of the parts that we - that I study - are the role of T-cells. So the same cells that are important in terms of fighting infectious disease that are knocked out by AIDS turn out to be some of the mischief-makers in terms of allergic disease sort of telling, sort of directing IgE production, telling cells to make IgE and causing inflammation locally. So I would say an antihistamine only blocks one of those mediators.

And it may be that other diseases, for example, asthma, doesn't work - is not well treated with antihistamines but other agents for the future that might be better blocking these other mediators, these other like - what we call interleukins - interleukin for things like that.

FLATOW: Is there lots of research going on not to just to create the drugs for the symptoms but to actually stop the allergic reaction from happening?

Dr. PRUSSIN: Very much so. So what - the NIH-funded research, other funded research in other countries is largely directed at trying to understand the basis - trying to use what we learned in the last 20 years in terms of the general immune system and try to apply that to allergic disease. And the reason is not so we know more only but so that we can then, once we know more we can develop better treatments, better ways to avoid these, better management strategies.

FLATOW: Because if I'm the chairman of a board of a drug company that makes the remedies I don't want a cure for this. I want to treat it forever. You know, why lose a patient. I can sell all those over-the-counters and prescription drugs for the remedy, you know, and then, you know…

Dr. KALINER: Ira, you know, you've done it sure for a long time, you know, there are very, very, very few diseases that are ever cured. Okay so…

FLATOW: And this one is not very harmful either.

Dr. KALINER: Well, it's extremely bothersome to the patient. So if, you know, what a quality of life measurement is?

FLATOW: Tell me.

Dr. KALINER: Okay so it's a way that we can asses in a number of domains how much bother a disease is to the patient. So it raises from everything that a patient feels about his life, then it's divided into seven domains. And when patients are asked their quality of life from hay fever - that bothers the nose - it is more bothersome to most patients than cancer and heart disease. So it may not be an important disease in terms of dying…


Dr. KALINER: …but it's an extremely disease for quality of life and in fact more money is spent on rhinitis and the treatment of rhinitis than most any other disease we take care of because people don't want to have sneezing, itching and running nose all the time.

FLATOW: Talking about allergies this hour on SCIENCE FRIDAY from NPR News. Let's see if I can get a quick question in from Miami. Terry(ph), hi, welcome to SCIENCE FRIDAY.

TERRY (Caller): Yes, hi. I am interested in the doctors response to certain alternative techniques that I've actually found very effective in treating allergies - neuro-modulation technique and NAET - that we've used in my family to actually get rid of both allergies to pollen and different things like that as well as food allergies and pet allergies. We've had really good luck with that in our family.

FLATOW: All right, let me see if I can get a question for - an answer for you, doctors?

Dr. PRUSSIN: The NIH has an institute - the National Center of Complementary and Alternative Medicine and they are trying to address some of these agents and these approaches. I should add that what Mike had just talked about the neti pot and the saline is the - one of the ultimate in terms of holistic or alternative therapies. But as a scientist and as a physician scientist I think it's important that we have an approach that uses a controlled clinical trial to understand these. And the reason is that for example asthma, when you treat asthma with a placebo 50, 60, 70 percent of the patients improve.

And so these diseases are very difficult to study without those types of placebo controlled studies. So it's not that these techniques don't work necessarily but we'd all like to see them studied in, you know, double-blind, placebo-controlled studies.

FLATOW: One of the stories about asthma over the years is that its possibly emotionally linked - is there any truth to that?

Dr. KALINER: Well, there's always stress and emotions have influences on how you feel and many body responses including asthma and allergies. But in terms of causation there are factors that make them worse but they don't cause the disease.

FLATOW: A question from Second Life from (unintelligible) - is local honey from local pollen useful for allergies? We've heard a lot about the bee honey.

Dr. KALINER: It's sweet.

FLATOW: It's sweet. What about bee pollen?

Dr. KALINER: Well, I remember about the - so getting to the relationship of bees and pollen and things like that, the bees pick up pollen that they - and they - when they're getting the nectar from the plants to make the honey. And the pollen itself if you eat that pollen and you're allergic to it you can have a severe reaction to it. So there was some again homeopathic approach where some people try to use bee pollen as a treatment for allergic disease and some patients got quite sick and nearly died, so that's dangerous. But the honey itself has no pollen allergen in it. So it's safe, it's sweet and I would recommend it for sweetening but not to treat your disease.

FLATOW: All right, we're going to take a short break and come back and talk lots more with Dr. Calman Prussin of NIH and Dr. Michael Kaliner who's at George Washington University School of Medicine - 1-800-989-8255. We'll talk a little bit more about that and also talk about pollen counting and tracking, pollen and mold and all these allergens that are flying and buzzing all around us. And why is pollen from grass different from pollen from flowers - interesting differences. Stay with us. We'll be right back after this short break. I'm Ira Flatow. This is SCIENCE FRIDAY from NPR News.

(Soundbite of music)

You're listening to SCIENCE FRIDAY from NPR News. I'm Ira Flatow, we're talking about allergy seasons with my guest Dr. Calman Prussin, Dr. Michael Kaliner, and my next guest has been tracking pollen and mold for the last 15 years. And he's here to talk about the pollen count. And if you look at the news we bring every night or maybe in the mornings on the local newscast you'll see this little graphs, shows you what the pollen and mold count is like. It's a color-coded sort of thing with different levels of pollen grains and mold spores and things like that.

Here to explain it is Dr. Jay Portnoy, he is the immediate past president of the American College of Allergy, Asthma and Immunology. He's also a chief of the section of Allergy, Asthma & Immunology at Children's Mercy Hospitals & Clinics in Kansas City, Missouri. Welcome to SCIENCE FRIDAY, Dr. Portnoy.

Dr. JAY PORTNOY (Former President, American College of Allergy, Asthma and Immunology; Chief, Section of Allergy, Asthma & Immunology, Children's Mercy Hospitals and Clinics, Missouri): Thanks for having me on Ira.

FLATOW: You're welcome. There's somebody actually going out there and counting every grain of pollen?

Dr. PORTNOY: Yeah, actually that's exactly right. First I wanted to say that I listen to your show every week. It's my favorite show and I just love the way you do things, so I think it's really a thrill to be on.

FLATOW: Thank you.

Dr. PORTNOY: We've been doing the pollen count for Kansas City for the last 15 years. And most people don't know how that count is actually done. What we have is a machine on the roof of our hospital that collects the air at a steady flow and it collects the air to a very narrow slid onto an adhesive-coated microscope slide. What happens is that the air flows around the slide and the particles impact on it because they have inertia. And so every 24 hours somebody goes up to the roof, replaces the old slide with a new slide and then we take it down to the laboratory where we have microscopists who stain the slide and then look at it and physically count the pollen grains one by one.

FLATOW: And you can tell and you do announce the different kinds of pollen from what resources.

Dr. PORTNOY: That's right. Because each of the pollen grains has a very characteristic appearance. In fact it's absolutely fascinating to take a look at these pollen grains. They have a variety of features on them that increase their aerodynamic buoyancies so that they can travel long distances from one plant to another. Some of them like golf balls, which in fact is one of the ways that we got the idea for shaping golf balls to look like that from pollens. Others have little air bladders on the side that keep them in the air and, you know, they do a variety of different things.

And by knowing what the pollens look like our trained microscopist can then identify each one, tally them up and the report it out as a count every day.

FLATOW: Now we were - we have our - the shows on the road in Arizona a couple of weeks ago and people from the East were saying, boy my allergies are really acting up out here in the desert, you know, we don't - we don't think of desert…

Dr. PORTNOY: Isn't that great, Ira? We love it.

(Soundbite of laughter)

Dr. PORTNOY: As an allergist it's job security for us.

(Soundbite of laughter)

Dr. PORTNOY: But really no matter where you go there's always something in the air that people can make an immune response to. In the desert there's more Bermuda grass, pollen and olive trees. In the Midwest, we have just regular deciduous tree pollens that starts in February and goes through April. It's a whole series of little mini seasons because each species of tree pollinates for about one or two weeks. Grass season is May and June, think of June grass. It's like one giant six-week allergy season and everybody is just miserable. And then in July the pollen drops off again and most allergists go on vacation. So we're well-taken care of.

September - August 15th is the first day of the ragweed season in Kansas City. We have a little celebration. You're welcome to join us someday if you'd like. It peaks on September 10th right after Labor Day and usually by early October the pollen count for ragweed drops off again.

FLATOW: Ragweed? No thank you. When I see ragweed I feel like I'm Dracula looking at a spike, you know, so like some garlic.

Dr. PORTNOY: (Unintelligible) look like too. They have these little spikes on them. And then - by the way, you know, we've been doing the pollen count for the last 15 years and what we found is that the tree pollen pollinates about two to three weeks earlier now than it did 15 years ago and the ragweed is lasting two to three weeks longer now. We attribute a lot of that to climate change. So, you know, global warming is having an effect on allergies…

FLATOW: Interesting. Is the pollen that we get out of the grasses like the grass itself different from the pollen we get out of flowers?

Dr. PORTNOY: Absolutely. Pollens come from plants that are entomophilus, the ones that cause allergy are anemophilus. Anemophilus plants, think of an anemometer, are wind pollinated. So, they don't need insects. That's why they're so much of those pollens that get into the air. Other plants that make flowers are entomophilus like entomology, they're insect pollinated. Those pollens tend to be larger and stickier so that the insects will carry it from one to the other.

That's why people tend not be allergic to flowers because the flowers don't release their pollen very much, but they are allergic to things that don't make flowers which we tend to call weeds.

FLATOW: And that's where the reaction is coming from.

Dr. PORTNOY: Right (unintelligible) the pollen.

FLATOW: And it's where…

Dr. PORTNOY: One other thing about the pollen is that it is subjected to a lot of stresses, so over time the pollen grains will break apart into smaller pieces, forming a bio-aerosol that's in the air, so even if you don't see large amounts of pollen on a specific day, there's a still a tremendous amount of the allergen floating in the air that may be free of the intact pollen grains.

FLATOW: Is the pollen count then very useful for folks who are suffering?

Dr. PORTNOY: Well, as Mike said earlier, the pollen count tells you what types of things are in the air. People who have had allergy testing know what they're allergic to, and so they can pay attention to what types of things are in the air at specific times, and that tells them that it's time to start taking their medication or see their allergist and get treated. Once the pollen count goes down again, then they know that they're all clear has sounded and they can go back out.

FLATOW: You know, we- we've heard that thunderstorms are bad for allergies, but doesn't the rain just wash the pollen out of the air then?

Dr. PORTNOY: Well, it does while it's raining, but what happens is that there is a front, a storm front, a wind front that goes in front of thunderstorms. That seems to blow pollen off of the plants and it also suspends mold spores into the air, and so you get this huge spike of pollen and mold pores right before thunderstorms. It accounts for something called thunderstorm asthma, so that there's actually an epidemic of asthma attacks that are seen in emergency rooms right around the onset of thunderstorms.

FLATOW: Quite interesting, sounds like you have a very interesting job, Dr. Portnoy.

Dr. PORTNOY: Oh, it's fascinating, we love doing it.

FLATOW: Thank you for taking time to be with us today. Good luck in the pollen season.

Dr. PORTNOY: Hey, thanks for having me on.

FLATOW: You're welcome. Dr. Jay Portnoy is the immediate past president of the American College of Allergy, Asthma and Immunology. He is also a chief of a section of Allergy, Asthma and Immunology at Children's Mercy Hospitals and Clinics in Kansas City, Missouri. Let me re-introduce my other guests. Dr. Calman Prussin, who is chief of the Lymphocyte Biology Section of the Laboratory of Allergic Diseases at the NIH, and that's the division - National Institute of Allergy and Infectious Diseases at NIH.

Dr. Michael Kaliner, professor of medicine at George Washington University School of Medicine and director of the Institute for Asthma and Allergy in Chevy Chase, Maryland. Our number, 1-800-989-8255. Lots of questions still to be asked. Let's go to Lisa from Savanna, Georgia. Hi, Lisa.

LISA (Caller): Hi there.

FLATOW: Hi there.

LISA: I just wanted to say I've been through a lot with allergies and I've found some things that have really helped me cope with allergies and I wanted to share it. For a long time I had crippling allergy symptoms. I was out of work a lot with sinus headaches once a week during the allergy season, which is already about ten months a year in Savanna. And I - couple of years ago I just got tired of it. I said I have to try different approaches. I was going through balancing the medicine symptoms versus the allergic reaction and - you know, I mean, which was making me sicker - the medications or the allergy, at a certain point?

And so I said, okay, let's try a different approach. I started saline rinse. I started going to a chiropractor and I got off of all the allergy medicines and started really forcing fluids, really drinking a lot of water. And I have taken those symptoms and knocked very severe allergies back to very minor allergies. And I'm not sure, you know, what in the combination of those things or possibly growing out coincident -growing out of the allergies coincidentally at the same time. But I - I really don't suffer very much anymore.

FLATOW: That's good to hear, that's good to hear. Let me get a reaction. Dr. Kaliner, any reaction to that?

Dr. KALINER: Well, I think we've got two very lucky people in the (unintelligible)…

(Soundbite of laughter)

Dr. KALINER: You and she should talk, Ira. Share your remedy.

(Soundbite of laughter)

FLATOW: There you go, well…

LISA: Alright, well, and there was one more thing. I have a young son and I was wondering if there is - if there is anything that I can do to help him not develop the type of allergies that I went through for so many years.

Dr. KALINER: Well, let me - again I don't want to be - I know I made a joke, but the reality is that allergy is an immune response caused by an antibody that's formed against the pollen grain, and that antibody is circulating, it's doing its thing. And chiropracty, which may have a variety of effects, has no influence whatsoever on allergic disease. So that's why I was making a joke about it. In terms of your son, he is going to be exposed to airborne allergens. You just cannot live in the United States, especially in a place like Georgia, and not be bath in allergens.

FLATOW: That's a good - that's a good point, because I want to thank - thanks for calling. I want to make a follow-up point about that, about stories that we have heard. And Kay Alerin(ph), who sent in a tweet on Twitter, says, What about kids growing up in too clean an environment? We have heard about research in the past years about that.

Dr. KALINER: Right.

FLATOW: You want to…

Dr. KALINER: So there's an area of research that's developed, what we call the hygiene hypothesis. And these are epidemiologic studies, studies of large groups of people, and they - some of them have been done in United States out of Tucson, some in Europe. And what almost all of them have shown is that at a very young age, from zero to one year of age, usually, that if you're exposed to let's say dirtier environments, meaning let's say, for example, daycare or having lot's of older siblings, kids that live on farms where the barn is actually attached to the house, have much lower rates of allergy and asthma when they get older.

And this agrees with the general thinking that if you think about our immune systems, our immune systems evolved over the last several million years to be in an environment where there is lot's of infectious diseases. And they have grown in a certain equilibrium with that. And so to suddenly change that over just the course of a couple generations to what are very clean environments where we don't have as many infectious diseases, is a huge change for the immune system, which it hasn't quite figured out how to cope with.

You think about it between a quarter and a half of all children would die before adulthood from infectious diseases, several hundred years and certainly in pre-historic times, and…

FLATOW: Let's go to the phones. Let's go to Brian from San Mateo. Hi, Brian.

BRIAN (Caller): Yes, hi. I have a different type of reaction to allergies. I don't get the runny nose and watery eyes as much, but it really affects my sleep. And I feel really drained during the day. Is that something that you hear much of or is there a lot of research on that?

FLATOW: I've heard of that one, yeah, I've heard of that one.

Dr. KALINER: There's not a lot of research in it, but when we go and do studies of patients, we find that fatigue, in large part because of the allergies and also because of sleep disorder breathing, so when your nose is congested, you don't breathe well, you snore and you get a much poorer quality of sleep. So those are the two factors. But even though in and of itself people who have the classic allergy symptoms but sleep okay are fatigued, and so they both combine to make it feel like you feel.

FLATOW: And of course they'll be taking some of those antihistamines?

Dr. KALINER: Then newer antihistamines are largely or completely non-sedating.

FLATOW: That's good to know. Okay. We've just about run out of time. Let me just remind everybody that I'm Ira Flatow and this is SCIENCE FRIDAY from NPR News, talking with Dr. Calman Prussin, who is chief of the Lymphocyte Biology Section of the Laboratory of Allergic Diseases and investigator at the National Institute of Allergy and Infectious Diseases in Bethesda; Dr. Michael Kaliner, professor of medicine at George Washington University, and also medical director of the Institute for Asthma and Allergy in Chevy Chase. Thank you, gentlemen, for taking time to be with us, and an allergy free season to you.

(Soundbite of laughter)

Dr. KALINER: Thank you.

Dr. PRUSSIN: (Unintelligible) Ira.

FLATOW: Thanks for all your advice.

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