Build immunity to allergies

June 6, 2011— — Allergy season is at its worst in 10 years, meaning lots of itchy eyes, runny noses and wheezing lungs for the 93 million U.S. allergy sufferers out there.

“We are seeing a mini-crisis in New York City, among other U.S. cities, due to heavy winter and early spring precipitation that has caused more early, and sustained tree and grass pollens in many areas,” said Dr. Clifford Bassett, clinical assistant professor of medicine at the NYU School of Medicine and medical director of Allergy and Asthma Care of New York. “Secondary, we have seen a steady rise in pollen levels in many areas.”

But with all the information available on seasonal allergies, many people are still confused by the myths and facts about allergy suffering and relief.

“Patients frequently blame the cause of their allergy symptoms on the wrong thing,” said Dr. Stanley Fineman, clinical assistant professor in the division of allergy at Emory University School of Medicine in Atlanta. “It is important for patients suffering from allergies to find out exactly what is triggering their symptoms.”

So, here are nine common allergy myths that are often confused as facts.

1. Myth: Only take medication when showing symptoms of an allergy attack.

Experts say most allergy medications work best if they are already in the person’s system or immediately after exposure, even if the person has shown no allergic symptoms.

“For patients with asthma and allergic rhinitis, allergic inflammation in the airways can be present even if the person can’t feel it,” said Dr. James Li, chair of the allergy division at Mayo Clinic in Rochester, Minn. “It’s there smoldering. But it’s clear that, for patients with asthma, daily treatment can reduce the risk of asthma attacks.”

Even though a person might suffer from low levels of symptoms, as the season progresses, Li said, a person can experience complete obstruction of the nasal passage if it goes untreated.

“By that time, it’s almost too late to take a medication,” he said.

2. Myth: If you use one brand of allergy medication, you build a tolerance and it will stop working.

“This one comes up all the time,” Li said. “If someone has significant allergies, they may take a medication and it seems to be helping, but then the person develops more allergy trouble and they conclude that they developed a tolerance to the medication.”

Li said allergic reactions wax and wane with time. When symptoms are mild, many people believe their allergy medication is stronger and works better.

“Allergy symptoms progress, not because a person has built tolerance to the medication, but their allergies have gotten worse or exposure to the allergen has increased,” Li said.

3. Myth: Allergy shots only work in children.

Experts say allergy shots, or immunotherapy, have nothing to do with age and can offer relief at any time. The shots contain just enough of an allergen to stimulate the immune system, but not enough to cause an allergic reaction.

With each session, doctors increase the amount of allergen in the shot. The idea is for a person to build up a tolerance to the specific allergen over time.

Allergy Myths Debunked

“Although symptomatic medications may help some patients with seasonal allergies, allergen immunotherapy or allergy shots are the only treatment that changes an allergic patient’s immune sensitivity to the triggering allergen,” Emory’s Fineman said. “Allergen immunotherapy can help patients build a tolerance to the allergens and provide long-term relief, even after the injections are discontinued.”

4. Myth: Flowers are a leading allergy irritant.

Stop blaming the flowers. They’re pretty to look at and, experts say, it’s probably not your flowerbed that is causing your runny nose and itchy eyes.

Allergies are primarily caused by wind-pollinated plants; flowers are generally reproduced by insects. Flower pollen is much larger than pollen that comes from trees. Tree pollen can be spread through the air, which can then be breathed in by humans and cause those miserable reactions.

“This notion comes up because flowers have pollen that is highly visible,” said Li. “But that pollen does not become airborne and there are not high concentrations of it in the air, like the pollens from trees, grasses and ragweed.”

5. Myth: Eat the local honey and you won’t get seasonal allergies.

The idea makes sense. Honey is made by bees. Bees are carriers of pollen, so bits of pollen may get into the honey. Eat the local honey and you may build up a tolerance to those allergens, as a whole. But experts say this is wishful thinking.

“Honeybees pollinate larger flowers,” said Dr. Michael Daines, an allergist and immunologist at the University of Arizona School of Medicine in Tucson. “These flowers produce large sticky grains of pollen that adhere to the bee. Large sticky grains of pollen don’t get in the air we breathe, so they don’t cause allergies. So even if local honey had enough pollen in it to desensitize your allergies, it would be the wrong kind of pollen.”

“Most importantly, this has been studied in clinical trials that show that there is no effect of unpasteurized locally made honey on allergies,” Daines added.

6. Myth: If you didn’t have allergies as a child, you’re in the clear as an adult.

Sorry folks, but even if you’ve lived an allergy-free life so far, it is indeed possible for you to develop allergic reactions in adulthood.

“Years ago, people thought that allergy was a childhood phenomenon,” Fineman said. “We now know the immunologic mechanism and realize that people with allergies have a genetic predisposition to develop an allergy; this can occur at any time even adults can develop allergy symptoms.”

New exposures may trigger allergic reactions to allergens. For example, if a person never had a pet before, a new dog or cat may trigger an unknown allergy, or a new location may trigger allergies that are specific to that region.

Sensitivity to allergens can also change with time, which might provoke more or less of an allergic reaction in the body.

7. Myth: Clean your house and your allergic reactions will disappear.

This would make sense: If someone is allergic to mold and dust, removing those things in the home would help to reduce the exposure and, in turn, allergy symptoms.

But doctors say that might not be true.

“There’s a hypothesis gaining traction that younger children exposed to dirty environments might be less likely to develop allergies,” Mayo’s Li said.

Li said children’s immune systems learn to fight the germs, and so the development of allergies is less likely to occur in a germy environment.

While this doesn’t give anyone the go-ahead to skip out on the household chores, it should make someone think twice about bleaching their entire home in the hopes of getting rid of allergens.

The American College of Allergy, Asthma and Immunology suggests keeping windows closed to cut down on pollen coming into the house, leave shoes at the door to avoid allergens and shower at the end of the day to cut down on pollen particles that can be brought into bed.

8. Myth: An allergy to one thing means you’ll react only to that.

“This word ‘only’ is always an issue anyway,” said Dr. Leonard Bielory, director of STARx Allergy and Asthma Center in Springfield, N.J. “Something can always be cross-reactive with something else. For example, if you’re allergic to ragweed, you can also be allergic to chamomile.”

Experts said that having some allergies might make a person more prone to being allergic to others.

About one-third of people with pollen allergies might react to certain foods, according to the American College of Allergy, Asthma and Immunology. If a person is allergic to tree pollen, that same person might also have a reaction to certain plant-based foods, such as apples, cherries, almonds and walnuts.

9. Myth: Short-haired pets won’t irritate allergies.

Contrary to popular belief, it is not a pet’s hair that causes allergic reactions in people, but the animal’s saliva and urine. So, really, doctors said the length of the dog or cat’s hair does not make a difference in allergic reactions.

When pets lick themselves to stay clean, allergens are released into the air.

“If someone believes mistakenly that allergy is related to the hair of the pet, it might seem logical that a short-haired pet would cause less trouble than long-haired, but any animal, especially dogs and cats, have potential to generate allergies,” Li said.

“Also, an individual may have one problem with one kind of pet, and they mistakenly attribute it to long- versus short-haired.”

And along with the bodily fluids, the animal’s skin can also be an allergen source.

“Patients with animal allergy are usually sensitive to the dander, or shed skin, of the pet,” Fineman of Emory University said. “All furred pets have dander, so short-haired pets can also cause problems for patients with animal allergy.”

Educating the immune system to prevent allergies

“Our study, for the first time, offers a potential way of preventing allergies by using a molecule that redirects the immune response away from the allergic response,” says lead author Dr. Christine McCusker, allergist at the Montreal Children’s Hospital and researcher at the RI-MUHC. “This discovery is very promising since the molecule we developed can be administered by a drop into the nose as a spray.”

It is estimated that 20 to 30 per cent of the Canadian population suffers from a range of allergies. Recent research reported that one in every 13 Canadians suffers from a significant food allergy. The reasons why allergies develop remain unexplained, but it is believed that all children are born with the potential to develop allergies. Children without allergies make a shift to the non-allergenic immune response when allergens are around. Those who do develop allergies have not shifted by the time they are exposed to the allergen.

Dr. McCusker and her team from the Meakins-Christie Laboratories started to work on a specific molecule — called STAT6 — which is important in the development of allergic response. They thought that if they could inhibit this molecule they would reduce the symptoms of allergic airways disease, such as asthma, in allergic animals. They also hoped to prevent the allergy from developing entirely. To do this, they developed an inhibitor peptide called STAT6-IP that was given to newborn mice by intranasal droplet.

“By giving the peptide STAT6-IP very early on, before allergies are present, we were able to teach the immune system. So when we tried to make the mice allergic later on, we couldn’t because the immune system had ‘learned’ to tolerate allergens,” explains Dr. McCusker who is also an associate professor in the Department of Pediatrics at McGill University.

“What’s beautiful about our approach is that you do not have to couple it with a specific allergen, you only use this peptide. It just redirects the immune system away from the allergic response and then it will not matter if the child is exposed to pollen, cats or dogs, because the immune system will not form an aggressive allergic reaction anymore,” adds Dr. McCusker.

“In subjects who have the propensity to develop allergies, their system has made the ‘wrong’ decision somewhere along the line,” she says. “It is like educating the immune system to follow the path we want it to follow.”

Researchers are now studying the effect of this peptide to see in what other areas this type of immune education will prevent disease, such as with food allergies. They then hope to move this discovery to clinical trials in humans.

Immune Tolerance in Allergy & Asthma

Allergy and asthma are intertwined in many ways. Allergies during infancy often precede the development of asthma. Additionally, Allergies can worsen asthma and induce an attack. Allergies occur when the body’s immune system over-reacts to a more or less harmless substance. Food and drug allergies can be particularly dangerous, as they can often cause anaphylaxis, a rapid and severe reaction that can lead to shock.

The available treatments for allergies are varied and only relieve symptoms without curing the underlying problem. A technique called “allergen immunotherapy,” where regular, repeated administration of the allergen over a long period of time, done under the supervision of physicians, can induce desensitization for some allergies. Unfortunately, while it has been confirmed to work for certain airborne allergens, it has not been proven to be permanent.

The Immune Tolerance Network (ITN) is seeking to develop new, improved methods of combating allergy and asthma that will be durable while requiring a much shorter treatment period, with higher rates of success than conventional immunotherapy. The ITN is also interested in finding ways to prevent the development of allergies, and the asthma that often results, in young children.

Research Focus – Allergy & Asthma

The ITN’s portfolio has focused on modifying validated desensitization protocols to induce durable tolerance. These studies were designed to test whether allergens could induce tolerance by altering the allergen structure, the timing of administration or the route of administration, and whether early allergen introduction in at-risk children could prevent future allergies. The ITN is currently developing novel trials to advance desensitization to true tolerance by focusing on combination therapies that administer allergen in the context of an immune modifying therapy (called “allergen plus”). The goal is to target known allergic pathways in a manner that will facilitate non-inflammatory recognition and processing of antigens to enhance the efficacy and safety of immunotherapy. The ITN will also continue to explore new allergen preparations and routes of administration to maximize the effectiveness of true tolerogenic protocols.

The ITN is also pioneering the in vitro definition of allergen-specific tolerance. As part of this effort the ITN has initiated a set of pilot studies to map detailed, time-dependent immune responses to allergen immunotherapy, as well as to refine methodologies for optimal specimen collection and processing. The goal is to use this information to design treatment regimens and clinical studies that better target allergic pathways and promote tolerance.

Allergy treatment: Scientists claim breakthrough that could lead to cure for all intolerances

Scientists in Australia claim to have discovered what could be a life-long cure for potentially fatal allergies to peanuts, shellfish and other food.

The researchers said they had been able to “turn off” the allergic response in tests on mice using gene therapy to desensitise the body’s immune system, and suggested this could also be used to treat asthma.

They predicted human trials could begin in just five or six years.

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Commenting on the study, a leading British expert said scientists had managed to cure allergies in mice before without this leading to an effective human treatment, but added that the new research could lead to the “Holy Grail” of allergy treatment.

He was sceptical about the researchers’ claims their technique might be effective against asthma, but Asthma UK said it was “a very exciting step forward”.

Allergies occur when the immune system over-reacts to something that is usually harmless. In the journal JCI Insight, the Australian researchers reported they had used genetic techniques to prevent this from happening in mice who were allergic to the protein in egg whites.

In a video about the new research, Professor Ray Steptoe, of Queensland University, said: “We can actually turn off the response. What that means is the disease is stopped in its tracks.

“What we do is we stop the underlying disease that causes these symptoms. That could revolutionise treatment for severe allergies. It would prevent, we think, some of the life-threatening allergic episodes that occur for people who are allergic to foods for instance.

“That would make a huge difference for people with severe allergies … what that would mean is they would no longer be in fear of life-threatening incidents if they were to go to a restaurant and be exposed to shellfish and they weren’t aware that was in the food.

“Kids with peanut allergies … could go to school without any fear of being contaminated from other kids’ food.

“We envisage in the future, with this approach, that they could go to the doctors’ rooms, get a single treatment and that would give them permanent protection from future allergic attacks or asthma attacks.”

He added that the researchers hoped human trials could begin in five to six years, estimated it would take a similar period after that for the treatment to be available to patients.

Professor Adnan Custovic, an allergy expert at Imperial College London, expressed particular caution about the claim the treatment would be effective against asthma as the condition is caused by a “completely different mechanism” to the one behind food allergies.

But he added: “This is one of the potentially exciting approaches to treating allergies.

“It’s sort of approach, where you try to switch off the allergic response, is kind of the Holy Grail, but a mouse model is not the same as a human model.

“We can cure allergies in mice but we cannot do it in humans … the mechanisms are not identical. Only time will tell whether this approach will be a viable one.”

Shape Created with Sketch. The worst jobs for your health

Show all 10 left Created with Sketch. right Created with Sketch.

1/10 10. Surgical and medical assistants, technologists, and technicians

Overall unhealthiness score: 57.3 What they do: Assist in operations, under the supervision of surgeons, registered nurses, or other surgical personnel and perform medical laboratory tests. Top three health risks: 1. Exposure to disease and infections: 88 2. Exposure to contaminants: 80 3. Exposure to hazardous conditions: 69

2/10 9. Stationary engineers and boiler operators

Overall unhealthiness score: 57.7 What they do: Operate or maintain stationary engines, boilers, or other mechanical equipment to provide utilities for buildings or industrial processes. Top three health risks: 1. Exposure to contaminants: 99 2. Exposure to hazardous conditions: 89 3. Exposure to minor burns, cuts, bites, or stings: 84

3/10 8. Water and wastewater treatment plant and system operators

Overall unhealthiness score: 58.2 What they do: Operate or control an entire process or system of machines, often through the use of control boards, to transfer or treat water or wastewater. Top three health risks: 1. Exposure to contaminants: 97 2. Exposure to hazardous conditions: 80 3. Exposure to minor burns, cuts, bites, or stings: 74

4/10 7. Histotechnologists and histologic technicians

Overall unhealthiness score: 59.0 What they do: Prepare histologic slides from tissue sections for microscopic examination and diagnosis by pathologists. Top three health risks: 1. Exposure to hazardous conditions: 88 2. Exposure to contaminants: 76 3. Exposure to disease and infections: 75

5/10 6. Immigration and customs inspectors

Overall unhealthiness score: 59.3 What they do: Investigate and inspect people, common carriers, goods, and merchandise, arriving in or departing from the US or between states to detect violations of immigration and customs laws and regulations. Top three health risks: 1. Exposure to contaminants: 78 2. Exposure to disease and infections: 63 3. Exposure to radiation: 62

6/10 5. Podiatrists

Overall unhealthiness score: 60.2 What they do: Diagnose and treat diseases and deformities of the human foot. Top three health risks: 1. Exposure to disease and infections: 87 2. Exposure to radiation: 69 3. Exposure to contaminants: 67

7/10 4. Veterinarians, veterinary assistants, and laboratory animal caretakers and veterinary technologists and technicians

What they do: Diagnose, treat, or research diseases and injuries of animals and perform medical tests in a laboratory environment for use in the treatment and diagnosis of diseases in animals. Top three health risks: 1. Exposure to disease and infections: 81 2. Exposure to minor burns, cuts, bites, or stings: 75 3. Exposure to contaminants: 74

8/10 3. Anesthesiologists, nurse anesthetists, and anesthesiologist assistants

Overall unhealthiness score: 62.3 What they do: Administer anesthetics or sedatives during medical procedures, and help patients in recovering from anesthesia. Top three health risks: 1. Exposure to disease and infections: 94 2. Exposure to contaminants: 80 3. Exposure to radiation: 74

9/10 2. Flight attendants

What they do: Provide personal services to ensure the safety, security, and comfort of airline passengers during flight. Greet passengers, verify tickets, explain use of safety equipment, and serve food or beverages. Top three health risks: 1. Exposure to contaminants: 88 2. Exposure to disease and infections: 77 3. Exposure to minor burns, cuts, bites, or stings: 69

10/10 1. Dentists, dental surgeons, and dental assistants

Overall unhealthiness score: 65.4 What they do: Examine, diagnose, and treat diseases, injuries, and malformations of teeth and gums. May treat diseases of nerve, pulp, and other dental tissues affecting oral hygiene and retention of teeth. May fit dental appliances or provide preventive care. Top three health risks: 1. Exposure to contaminants: 84 2. Exposure to disease and infections: 75 3. Time spent sitting: 67 Overall unhealthiness score: 65.4 What they do: Examine, diagnose, and treat diseases, injuries, and malformations of teeth and gums. May treat diseases of nerve, pulp, and other dental tissues affecting oral hygiene and retention of teeth. May fit dental appliances or provide preventive care. Top three health risks: 1. Exposure to contaminants: 84 2. Exposure to disease and infections: 75 3. Time spent sitting: 67

And he criticised the degree of optimism about the technique expressed by the Australian team.

“My real problem with this sort of bombastic statements like this is people with asthma … it gives them hope which very often is not realistic,” Professor Custovic said.

However Dr Erika Kennington, head of research at Asthma UK, was more optimistic.

“This is potentially a very exciting step forward in asthma research,” she said.

“Allergen immunotherapy – exposing people to small amounts of an allergen in order to build up tolerance – is currently the only disease-altering treatment available for asthma but it can have significant side effects in some people, and every other existing asthma treatment and medication works by reducing or relieving the symptoms.

“These findings suggesting a novel approach to reversing allergic disease are therefore very welcome.

“We also know that there are certain allergy triggers that cause asthma flare ups, which makes this research important in possibly reducing the risk of life-threatening asthma attacks.”

But Dr Kennington also pointed to the difference between animal and human trials.

“A lot more research is needed to see if the same results can be achieved in people before we can say that a cure for asthma is around the corner,” she said.

In the study of the allergic mice, the researchers inserted a gene into blood stem cells that controls the immune response to the egg white.

The genetically modified cells were then injected into the mice’s bone marrow, where they produced new blood cells that were able to “turn off” the allergic response.

The researchers hope to create a similar form of gene therapy that works on humans after a single injection.

“We haven’t quite got it to the point where it’s as simple as getting a flu jab, so we are working on making it simpler and safer so it could be used across a wide cross-section of affected individuals,” Dr Steptoe said.

Dr Louisa James, British Society for Immunology spokesperson and an immunologist at Queen Mary University of London, said allergies were “far more complex than can be replicated in an animal model”.

“Patients with severe allergies often react to several different types of allergen and symptoms can develop over several years,” she said.

“Although the results are encouraging and heading in the right direction, it is too early to predict whether this form of therapy could ever be used to treat allergies in humans.

“As the authors state in their paper ‘gene-therapy is not yet suitable for clinical application to mild disease in young individuals’.

“There are simply too many open questions around the translation of these findings from animal models into humans. Would the cells engineered to produce allergens produce the same response in humans? How would other immune cells that play a critical role in human allergy be affected? What are the mechanisms that ‘switch off’ the immune response and are they comparable in humans?

“This approach holds promise, and further research is certainly warranted, but claims that a single injection could switch off allergies are over-optimistic at this time.”

IRA FLATOW: We have a tweet from Karen who says, how does heredity factor into allergies? Good question.


SUSAN LYNCH: That’s a really good question.

MATTHEW RANK: Please, go ahead.

SUSAN LYNCH: Sure, sorry. There’s certainly risk genes that have been associated with increased chances of developing allergies and asthma, things like ORMDL3 and so there is clearly a hereditary component of this. But I think that the rapid increase in the rate and prevalence of allergic disease over the last several decades suggests that this is not simply down to host genetics.

I would also like the audience to think, as well, that it’s not just host genes that we pass on to our offspring. There’s actually microbes that are transmitted vertically from mother to child during the birthing process. So it’s not just host genes, it’s microbial genes, as well, that might be driving some of this, and that vertical transmission may be compounded over generations. It’s one of the hypotheses in the field right now.

IRA FLATOW: That brings me to Jessica in Murray, Kentucky, who might have a comment about that. Hi, Jessica.

JESSICA: Hi. I was wondering, is, in the studies looking at infants, in particular, if you saw any impact of breastfeeding with regard to the intestinal flora.

SUSAN LYNCH: We certainly know from studies outside of our own that breastfeeding appears to promote the types of organisms that produce molecules that allow us to respond appropriately to allergens, that allow us to quench allergic responses. In our study of the one-month-old babies, we actually did not see a significant difference in breastfeeding frequency between the high risk and the lower risk groups. But that may be because our numbers are small. We had 11 children who were in the high risk group. So that’s always a caution with smaller studies. And we certainly know that breastfeeding is associated with promotion of the types of organisms that we need to quench allergic response.

IRA FLATOW: Here’s a tweet, came in from morningmorning, who says, “been eating honey from a hive in my hood.” I imagine that’s raw honey. I haven’t had to take medications. Coincidence? I’ve heard a lot of anecdotal stuff about honey.

MATTHEW RANK: We have a lot of patients coming and asking us about this. And like with a lot of different treatment options in allergy, some have been studied better than others, some we have more confidence in how well they work. Local honey is one of those treatments where we really just don’t know how well it works. We really don’t have the studies with the right rigor that we need to judge how effective it may be. I usually steer patients to treatments that we know may be more– that we have more confidence that they’re effective, but I don’t discount the possibility that this could be an effective treatment after we’ve studied it more carefully.

IRA FLATOW: And because there’s no money, really, if it’s local honey, and doing a study.

MATTHEW RANK: That’s right. The support would have to come from somebody who really wanted to do that study and wouldn’t potentially be able to benefit monetarily.

IRA FLATOW: That’s 100 million bucks we’re talking about, something like that. Let’s go to Maryland. Andrea, in Maryland. Hi. Welcome.

ANDREA: Hi there. Thank you for taking my call. I want to start with a quick history before I ask my question. Well then, about two years ago, at the advice of my father’s a nutritionist, who has been for many years, I dropped all dairy from my diet. And I started probiotics and prebiotics. And I have not had any seasonal allergies for the last two seasons since I changed my diet. So here’s my question– is it possible that you have, as I try to explain it to people, you have x number of soldiers that are fighting your allergies. And if you have a food allergy that you don’t know about, that’s using up some of the soldiers and you don’t have enough– your immune system is not strong enough or doesn’t have enough of these quote unquote soldiers to fight the seasonal allergies that you’re discussing?

IRA FLATOW: Dr. Lynch, Dr. Rank? Calling Dr. Lynch, Dr. Rank.

SUSAN LYNCH: Sure. I think a change in diet begets a change in the types of microbes and their products in the gastrointestinal tract. That’s a given. And the fact that you’re seeing a change of diet also with an introduction of probiotics as being beneficial is quite interesting, because it mirrors a study that was performed in infants with cow’s milk allergy.

Those infants who received cow’s milk with a Lactobacillus supplemented into the cow’s milk actually showed a significant reduction in their cow’s milk allergy following a year of that type of mode of feeding. So I think what it suggests, and your anecdotal evidence suggests, as well, is that it may be a combination of providing the right foodstuffs as well as the right microbial machines to convert those foods into molecules that reduce inflammation and allergic responses.

IRA FLATOW: Let’s talk–


IRA FLATOW: Oh, I’m sorry. Go ahead. I’m sorry, Dr. Rank.

MATTHEW RANK: I would completely agree with the mechanistic suggestion from Dr. Lynch. I would add, though, a note of caution that we really don’t know how well those dietary changes or those pre- or probiotics will work in reversing or changing immune tolerance. We still have a lot more work to do in that field.

IRA FLATOW: A couple of questions. One from my own experience and one from people who’ve been asking about nut allergies. How come– when I was growing up, I never heard the word, “nut allergies”. Is it just going undiscovered, so to speak?

MATTHEW RANK: Maybe let me start with that one. But I do want to give Dr. Lynch a chance as well for this one. We think there’s been a significant increase in nut allergies, and we think this is likely related to a number of factors. A number that Dr. Lynch already mentioned– changes in lifestyle, changes in diet, changes in antibiotics, changes in our microbiome. And we don’t fully and completely understand the relative contribution of each of these factors, but we’ve clearly observed, I think most would agree, an increased prevalence in all these food allergies.

IRA FLATOW: An increased prevalence in food allergies? Wow. And any hypothesis why that might be?

SUSAN LYNCH: There’s a number of theories, I think. I think we’ve changed quite dramatically how we produce food and that may also change the content of the food. And indeed, even the microbial payload that comes along with the food. Microbes do not have to be live to induce an immune response. I think that that’s an important point to be considered. The sugars that decorate their membranes and their DNA themselves can act as signals to provoke an immune response.

But I’d like to also mention a really, very quite elegant study that was published in the New England Journal of Medicine a couple of years ago. I think the idea for a number of years has been that if we avoid allergens that that would help promote tolerance to them. And in fact, quite the opposite has been shown in a study of very young children, in which early life exposure to peanut products significantly reduced the incidence of peanut allergic responses in those children. It was really a quite eye-opening study that really turned on its head this idea that allergen exposure may be the appropriate approach to prevent allergies.

IRA FLATOW: It’s interesting, because we had a tweet from Sharon– it was actually on Facebook that it came in, and it said, “I have recently developed an allergy to animal dander after taking a job in a vet clinic. Can increased exposure cause an allergy or does the change in exposure ramp up an existing one?”

MATTHEW RANK: Yeah. That’s a great question. We see a lot of people that are having symptoms around their pets. We see a lot of people working in labs or working in vet offices that come in with animal dander allergy. And some people can completely tolerate that without developing an allergy. Others will develop that allergy. And the rate or the exposure rate to that is not always clearly the reason for why that happens.

We believe that people have a genetic predisposition to potentially develop allergy and the environmental exposures that happen along the way, perhaps significant influenced by the microbiome, are what ultimately influence whether that person develops an allergy. And it’s quite variable, and at least from where I sit in the clinic, talking to patients with allergies every day.

IRA FLATOW: Well, that, because– another Facebook from John says something very interesting along those lines, which is, “some allergies seem to sensitize with repeated exposure, meaning shellfish, while some habituate with low incremental increasing doses, such as peanut and nut allergies. Why is that?” One thing– ying and yang and that.

MATTHEW RANK: I think that really gets to the heart of how immune tolerance is developed and the timing of when those exposures occur, the frequency and the dosing– all those things matter quite a bit.

What’s happening right now– and Dr. Lynch nicely highlighted– is a shift in our approach to thinking about food allergy and trying to promote tolerance. That very important study she mentioned, called the LEAP study, where before, we thought, oh, if we just don’t expose children to foods during that critical time or they may develop food allergy, they just won’t end up developing that food allergy. In fact, with really carefully designed trials, we found that wasn’t the case at all. In fact, we need to expose children earlier to train their immune system to tolerate those things, so that early life frame is critical. Whereas later in life, it may not be so critical.

On the other hand, there are plenty of adults that develop allergy– hay fever, seasonal allergies, asthma-type problems, food allergies. So it’s not that– it’s not the same– it doesn’t work that way for everybody.

IRA FLATOW: I’m Ira Flatow. This is Science Friday from PRI, Public Radio International. Talking about allergies with Dr. Susan Lynch, associate professor of medicine at UC San Francisco and Dr. Matthew Rank, associate professor of medicine at the Mayo Clinic School of Medicine in Scottsdale, not in Rochester, Scottsdale.

It seems like this is such an incredible– we could go on all day. I have a lit up board of phone calls and tweets coming in. It’s something everybody– and now, I guess, this time of the year. And let me ask you, because we only have a few minutes left– is this a bad or worse year than normal that you’ve seen? Let me ask you, Dr. Rank and then Dr. Lynch.

MATTHEW RANK: Sure. Most who’ve looked at the data would say that each year may be a little bit worse. There are several factors that may contribute to this. One of them is urbanization. So actually, we grow and plant things, and they seem to grow better when it’s warmer on heat islands in urban areas, and some allergens grow better in conditions in our polluted air.

The second factor is overall warmth of temperature across our country and across the world. There are longer pollen seasons. And this promotes more pollen to develop. And so each year, we may expect to see this be a little bit worse. Pretty clear that the pollen seasons the further we get away from the equator have significantly lengthened in time.

IRA FLATOW: Climate change. Yeah. Dr. Lynch, do you agree?

SUSAN LYNCH: I agree. I agree wholeheartedly. And again, it may be, again, about that, as the earlier caller mentioned, that increased and prolonged exposure may be part of the issue.

IRA FLATOW: And so, the first thing that people should do if you say that later in life they can develop allergies is go see your physician and try to figure out what it is first. Get those allergy tests. I had 100 allergy tests on my arm years ago. Both arms. Are they still doing that?

MATTHEW RANK: Yep. That’s still one of the best ways to determine if somebody’s sensitive to a particular allergen. The reaction on the skin tends to mimic pretty well what happens in the gut or happens in the nose or lungs. Not perfect. There are some additional advanced diagnostic tools that people are working on. It

IRA FLATOW: Was I just lucky that I grew out of it? Just something we don’t know why?

MATTHEW RANK: Well, we think that being on allergy shots and training the immune system in that way helps people outgrow them. Often, for a long time. It’s one of the ways to try to retrain the immune system after someone’s already acquired allergy.

IRA FLATOW: All right. Thank you very much. As I say, we’ve got lots of people. We’ll send them to our website to get some of the resources. Dr. Susan Lynch, associate professor of medicine, UC San Francisco. Dr. Matthew Rank, associate professor– I don’t why I can’t get that “professor” out– of medicine at the Mayo Clinic School of Medicine in Scottsdale.

In Scottsdale, was that the place people went to get away from allergies? Not so much so anymore?

MATTHEW RANK: Used to be.

IRA FLATOW: Used to be. That’s– Thank you both for taking time to be with us today.

After the break, an innovation that melds muscles and nerves in an amputated limb and could bring more sensory feedback to bionic limbs. We are still doing amputations like we did during the Civil War. Maybe that will change now that we have bionic limbs and we want to hook up the muscles to them. We’ll talk about it after the break. So stay with us.

Living With Food Allergies

If you want to learn more about research for food allergies, I would encourage you to go to the American Academy of Allergy, Asthma, and Immunology at or read about the studies themselves at (which is the site where most of the trials are registered).

What is ahead?

I remember the days when no one had e-mail or cell phones. My childhood phone had a curly cord connected to a base that had a rotary dial. In someone’s imagination, there was a cell phone and then text messaging. Maybe one of these treatments is the next cell phone for the field of food allergy. Perhaps a brilliant scientist is dreaming up this idea right now and in the coming years, we’ll see some more exciting research emerge. We can only guess what lies in the future, but for food allergies, it is definitely bright.

Michael Land, MD, FAAAAI, is a medical advisor to Kids With Food Allergies.

Dr. Land works in the Allergy Department at Kaiser Permanente in San Diego, CA. He is also the Associate Training Program Director for the UCSD Allergy/Immunology fellowship program and Volunteer Clinical Assistant Professor with the UCSD Department of Pediatrics. Prior to moving to San Diego, he was an Assistant Professor of Pediatrics in the Division of Allergy/Immunology at Duke University School of Medicine. Dr. Land has a special interest in food allergy as a parent of a food allergic child and has 4 family members with food allergies. His practice focuses on children and adults with allergic and immunologic disorders.

Dr. Land grew up in North Carolina and attended the University of North Carolina at Chapel Hill, followed by Wake Forest University School of Medicine. He decided to move out west for a change and matched at the UCLA Medical Center for residency in pediatrics, followed by his fellowship in allergy/immunology there. After finishing fellowship, he joined the faculty at Duke, where he participated in research and teaching for the Allergy/Immunology training program for 4 years. Dr. Land worked closely at Duke with Dr. Wesley Burks, one of the world’s leading food allergy experts and a lead researcher in immunotherapy for food allergies.

After having 2 rambunctious boys, Dr. Land and his wife decided it was time to head back to sunny Southern California. He is active in the San Diego Allergy Society where he currently serves as Vice-President, and the American Academy of Allergy, Asthma, and Immunology, where he serves as Past-Chair of the New Allergist/Immunologist Assembly and Chair of the Complementary and Alternative Practices in Allergy Committee.

Medical review December 2014.

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