Episode transcript
Time stamps
0:51 - What is allergic asthma?
3:15 – NIH guidelines on allergic asthma
7:15 – Thunderstorm asthma and other non-allergic triggers.
10:50 -Exposure reduction techniques for managing asthma.
12:22 – CDC guidelines for allergic asthma.
16:45 - Summarizing today’s discussion points.
Announcer:
ImmunoCAST is brought to you by Thermo Fisher Scientific, creators of ImmunoCAP™ Specific IgE Diagnostics and Phadia™ Laboratory Systems.
Gary Falcetano:
I'm Gary Falcetano, a licensed PA with over 11 years experience in allergy and immunology.
Luke Lemons:
And I'm Luke Lemons with over five years of experience writing for healthcare providers and educating on allergies. You're listening to ImmunoCAST your source for medically and scientifically backed allergy insights.
Today we're going to be talking about allergic asthma, and this is a curbside console episode. So we're going to be focusing a little more on the guidelines and where allergic asthma sits in the clinic and patients who may be suffering from it and how to help them, and also how to manage symptoms. So Gary, allergic asthma.
Gary Falcetano:
Allergic asthma, Luke. So yeah, so allergic asthma makes up a majority of the asthma phenotypes that we see. So we'll talk about some of the statistics in a minute, but I think it's really important that in this episode we think about exactly how people's allergy really plays into their symptoms and how we can really help them to better manage those symptoms by identifying those allergies.
Luke Lemons:
So why don't we start with what is allergic asthma, which you'd think it's in the name, it's allergic asthma, but let's talk a little about the unified airway.
Gary Falcetano:
Yeah, sure. So I think as you mentioned, there are multiple types of asthma, right? It's a pretty heterogeneous type of disease, but the major phenotype for asthma patients is allergic asthma. And you mentioned the unified airway, and basically what that means is it's one airway from the tip of the nose into the alveoli in the lungs. And what affects one part of that airway often affects the other part of the airway. And we know that with children, about 90% of children who have asthma also have allergy that affects their symptoms. With adults, that's around 60%. So as I said, a majority of patients do present with this phenotype, and it's important to kind of help them sort out what's driving those symptoms.
Luke Lemons:
So oftentimes when people think of allergies, they think of pollen, and that does contribute to symptoms of allergic asthma. But there's a ton of other triggers out there that can cause asthma flareups, especially if people are allergic to them, for example, dust mites, cockroaches, pet dander. On those, Gary, is there anything interesting that a provider may need to know about these specific triggers?
Gary Falcetano:
Well, I think on a previous episode we spoke about the symptom threshold and that allergies are a cumulative threshold disease. So I think that's especially important to keep in mind when we're talking about allergic asthma, because allergic asthma typically is being driven by more than one allergen, and they do stack on one another. Those indoor allergens in particular are pretty hard to identify, because they're perennial, right? They're year round, and we don't typically see seasons for those where we can predict their increases or decreases.
Luke Lemons:
And because of the way in which these triggers affect those with asthma, this is why the NIH guidelines for, I believe it's asthma, right Gary? The NIH guidelines, they recommend that patients who do have persistent asthma should be evaluated for the potential role of allergens, particularly these indoor allergens.
So dust mites, you had mentioned you had something on dust mites that was interesting.
Gary Falcetano:
Yeah, I think when we look at the exposure reduction recommendations for dust mites, I think we're all pretty aware of putting on dust mite allergen proof covers on pillows, mattresses, box springs, but I think it's really important and sometimes gets overlooked to really get at the source of the dust mite's life and that's how they drink. So yeah, it's kind of an interesting trivia fact that dust mites don't drink like you and I, or even like cockroaches drink, right? We typically have to find a water source, go to it and drink it. Dust mites actually absorb moisture from the air, so they have an area on the back of their shell, or carapace, where they actually absorb moisture. Without moisture in the air, they end up dying. So that's why we don't see dust mites in any big numbers at all in Denver, Colorado where there's almost no humidity. So humidity, especially in the bedroom, plays a big role in the levels of dust mites.
Luke Lemons:
And so, someone who has asthma, they probably have a humidifier in their room. And so you're saying that that's just feeding the, if they have a dust mite allergy, that's just feeding the dust mites?
Gary Falcetano:
Yeah, well, exactly. So a couple of big drivers of asthma are dust mites and mold, right? And if we have something in the bedroom, so basically a drinking fountain for those dust mites, we're doing exactly the opposite of what we should be doing. And you're absolutely right, people with asthma, especially children, I think parents often put a humidifier in the room to help them breathe a little easier if they have a dust mite allergy or if they have an identified mold allergy, it's one of the worst things we can do is actually put a humidifier in their bedroom.
Luke Lemons:
And so, when it comes to these triggers, dust mites, cockroaches, pet dander, you want to reduce. Again, Gary, you called out, we have an episode on symptom threshold, so check that out if you're curious on how that works and how reduction can help with asthma or allergy symptoms in general. But when it comes to asthma specifically, reducing allergens shows that symptoms become more manageable. Is that correct, Gary?
Gary Falcetano:
Yeah, that's exactly right. And I think, I talk to providers all over the country, and I think what I often hear is, well, we tell patients to do a lot of things, lose weight, eat better. Will they actually do some of these exposure reduction techniques that we tell them about? And if they actually do them, will it actually work? Will it matter in their disease?
I think there was a great study that was published a few years back in New England Journal. It was inner city asthma study. It looked at almost a thousand kids from inner city neighborhoods all around the country. So Boston, Atlanta, New York, Phoenix, and they randomized them into two groups, active, control. They both gave them the exact same kind of optimized treatment plans, educated them around their disease. The only difference was the active group was actually tested for their sensitizations, and they did bedroom only interventions to reduce their exposure to those things they were sensitized to. And they had some pretty dramatic results, Luke. They had almost three weeks less symptoms per year in the active group, almost a week's less missed school and two less unscheduled office visits or ER visits. And all with the only variable being identifying what they were sensitized to and reducing it in the bedroom. So not necessarily put them in a bubble, but doing those bedroom only interventions.
Luke Lemons:
That's so interesting. It makes sense though. It makes sense. You reduce the triggers and people can breathe easier. And so, there's the allergic triggers that affect asthma, but the non-allergic triggers out there. They may also have an impact on allergic asthma, even though a patient may not be allergic to a substance, for example, having a virus or a cold, that's not an allergy. It's not allergic. But we do see that when a patient does have a virus and they're sensitized and exposed to their allergens that they're allergic to, they have asthma. There's about a 20 fold increase in hospitalizations in these patients.
Gary Falcetano:
Yeah, that's exactly right. And what we're talking about here is airway inflammation, right? And there can be various factors to that. So someone with allergic asthma is experiencing a certain amount of inflammation when they're exposed to those allergens they're sensitized to. But then you can also have other inflammation, right? From either chemical, whether it be ozone or non-volatile organics, but specifically what you're speaking of is a viral illness, right? A viral or bacterial illness can also cause airway inflammation and all of that is additive, just like allergen exposure is additive. So is other things that cause airway inflammation.
Luke Lemons:
Yeah, we were talking outside of this recording, but another interesting non-allergic trigger is thunderstorms, for thunderstorm asthma. You're not allergic to the lightning. It hurts, but you're not allergic to it. But these storms, they cause updrafts and downdrafts and they end up bringing allergens into the atmosphere where they're kind of pulverized and can enter way easier into this unified airway and can cause asthma symptoms in patients. So when it rains, people may assume, oh, I'm allergic to rain, but it's a non-allergic trigger that ends up worsening the allergic trigger. It's just really interesting how this all plays together.
Gary Falcetano:
That's right. And the way that those allergens kind of get, as you mentioned, for lack of a better word, pulverized in the environment, it actually makes them into smaller particles that allows them to be carried deeper into the lungs so it can really exacerbate someone with allergic asthma.
There was a really kind of seminal event that happened in Australia back in 2016, and they had an amazing, not in a good way, amount of patients that had to be taken care of in a short period of time because of kind of a perfect storm of there being a lot of grass pollen around and having this big cold front came through that dropped temperature and caused these massive downdrafts from a thunderstorm. They ended up with actually 10 people dying from that thunderstorm asthma. And to put that in perspective, we typically see about 10 deaths from asthma per day in the United States.
Luke Lemons :
10 per day?
Gary Falcetano:
In the entire United States, and they saw this in a couple of hour period near Melbourne, Australia.
Luke Lemons:
And so speaking of those 10 patients a day who die from asthma, it's not just those who have severe asthma, correct? It's across the board on this disease state.
Gary Falcetano:
That's exactly right. When we look at their levels of severity, we actually see it almost equally divided from mild, moderate, and severe when classified by the NIH classification criteria.
Luke Lemons:
And that's just not because of thunderstorm asthma, right? That's like all-
Gary Falcetano:
Of course.
Luke Lemons:
Yeah. Okay. Yeah. So all those, that's wild. 10 a day.
Gary Falcetano:
Yeah. Now thunderstorm asthma isn't a huge issue, and we haven't seen any massive events here in the US, but it certainly, to your point, thunderstorms in different weather events can certainly exacerbate people's condition.
Luke Lemons:
And when it comes to pollen outside, you can't chop down the trees. We've been saying this throughout the episode, you can't go chopping down all the trees in your neighborhood because you have a pollen allergy, but to reduce exposure, like you were saying earlier in the bedroom, is a very helpful way to manage allergic asthma, and helps step patients down medication ultimately to get it more manageable, correct?
Gary Falcetano:
Exactly. If we can control the controllables, right, and prevent anything that they're allergic to outside of the bedroom from getting into the bedroom, if we can decrease the levels of things that are in the bedroom, like dust mites or mold, keeping pets out. And I think this is a common theme that we'll talk about in a lot of our podcasts, but it's really important to address this from a preventative medicine standpoint. There are really no side effects from doing some of these environmental exposure reduction techniques, and they can actually make medications more efficacious and hopefully have people on the lowest possible dose of their meds to achieve satisfactory control.
Luke Lemons:
I think it also speaks to the importance of knowing exactly what someone with asthma is allergic to, because if you don't know for certain what they're reacting to, it's hard to implement these management solutions.
Gary Falcetano:
Exactly. I mean, I think for each of the allergens, there's probably five or six different exposure reduction techniques that are recommended to reduce levels of allergen in someone's environment. We can tell them, for these five or eight different allergen types, these are things you should be doing. But if we can't pinpoint exactly where they need to target their efforts, it's going to be really hard to allow patients to be as adherent as they need to be to really see some effects.
Luke Lemons:
And I mentioned earlier the NIH guidelines and the importance of testing those who have persistent asthma, and we see the same recommendation from the CDC that says that children and adults with persistent asthma should receive some form of allergy testing, particularly for indoor allergens, because of these management options and in knowing is so impactful to these patients, just knowing what they are allergic to can help them and potentially save them if they know when they're at risk and where they need to be or can't be in their house.
Gary Falcetano:
Exactly. And I think we see that both with, as you mentioned, the CDC with NIH guidelines in the US, with GINA guidelines that are global. We see in all of these guidelines the importance of identifying allergic triggers for sure. One thing I think people don't realize too, in the NIH guidelines, testing for allergic triggers is actually considered category A evidence. So there's more evidence actually around testing for allergic triggers in patients with asthma than there is for recommending a flu shot. So we would never consider not recommending an influenza vaccine to a patient with asthma, but yet there's actually more evidence in asthma around identifying allergic triggers.
Luke Lemons:
It's such an important piece of knowledge for patients that have asthma or have allergies and asthma. And when a patient comes in and they do have asthma, it should be based on these guidelines, like a first step if they have patient history as well, right, because all testing should be done based on clinical history and then running a specific IgE test or some form of allergy testing.
Gary Falcetano:
Exactly. Well, with asthma, if they're presenting with symptoms consistent with asthma, that is all the indication you need to assess them for their respiratory allergens.
Luke Lemons:
Okay, so patients with asthma in general need to be tested?
Gary Falcetano:
Exactly, even outside of specific rhinitis symptoms. Certainly if they have rhinitis symptoms, it puts them at even greater risk of having an allergic phenotype and to their asthma. But the guidelines don't necessarily differentiate between someone who has, by history, rhinitis and asthma symptoms. Just if you have persistent asthma, so basically symptoms more than twice a week, right? Symptoms that require a controller medication, like an inhaled corticosteroid, those patients are, it's highly recommended that we assess them for their allergic triggers. And as you said, it's common sense. Right? If 90% of kids, 60% of adults have allergic triggers that potentially make their symptoms worse, why would you not want to know what those are and help them to reduce them?
Luke Lemons:
And any, well most providers can do this testing, correct? It doesn't have to be a pulmonologist or just an allergist. Because I can only imagine that when people first start showing symptoms of asthma, they're not booking a specialist appointment, right?
Gary Falcetano:
Well, exactly. And the other point to that is about 70% or more of patients with asthma are managed exclusively in the primary care setting. So it's very important for primary care providers, family practice, pediatricians, internal medicine providers to be able to do this type of testing. And then once that's completed, I think using that information to decide who needs additional referrals to specialists, whether it be pulmonology or allergy, depending on their need for specialized treatments like biologics, et cetera.
Luke Lemons:
Yeah. And the goal is to give them this valuable information as quick as possible instead of referring right away.
Gary Falcetano:
Well, exactly. And we've talked about this on previous episodes. We only have a little over 4,000 clinically practicing allergists in the US. We have 26 million people with asthma. Primary care needs to really maximize their scope and practice to the highest level of their abilities so that we can really save those allergists, those pulmonologists, for those patients that really can benefit from their expertise, not from a one-off allergy test, and be sent back to primary care for the rest of the management.
Luke Lemons:
Well, to wrap things up here, Gary, we talked a bit about the NIH guidelines, the CDC guidelines, as well as some studies around the impact of reducing triggers in those who have allergic asthma. So in all of these guidelines and these studies, they point towards making sure that patients know what they're allergic to and then just working towards managing their symptoms by reducing exposure.
Gary Falcetano:
That's exactly right. And also phenotyping to the non-allergic, right? Because if you have a non-allergic phenotype of asthma, then your recommendations can be different, and certainly your pharmacotherapeutics can be different as well.
Luke Lemons:
Well, if you would like more information on allergic asthma, visit this episode's specific page on thermofisher.com/immunocast, and we'll have some resources there and some of the studies and guidelines that we talked about today.
Gary Falcetano:
Thanks so much. We'll see you next time.
Announcer:
ImmunoCAST is brought to you by Thermo Fisher Scientific, creators of ImmunoCAP™ Specific IgE Diagnostics and Phadia™ Laboratory Systems. For more information on allergies and specific IgE testing, please visit thermofisher.com/immunocast. Specific IgE testing is an aid to healthcare providers in the diagnosis of allergy and cannot alone diagnose a clinical allergy. Clinical history alongside specific IgE testing is needed to diagnose a clinical allergy. The content of this podcast is not intended to be and should not be interpreted as, or substitute, professional medical advice, diagnosis, or treatment. Any medical questions pertaining to one's own health should be discussed with a healthcare provider
