We all know that asthma impacts breathing. What may be less known is that the disease, which restricts our airways due to inflammatory responses, can be caused throughout our lifetime by a variety of things. It can be treated in several ways, too, depending on the type of inflammatory response generated.  

From common environmental exposures, like pet dander, to those we may be less familiar with, like small particulates carried in wildfire smoke, asthma can be developed or worsened due to what we breathe. There are also genetic predispositions someone may inherit that make them more likely to develop the disease at some point in their life. For those with chronic disease, new prescription treatment options such as combination inhalers and injectable medications can help prevent recurrent flare-ups.

Tufts Now sat down with Jeremy Weinberger, an asthma expert, assistant clinical professor at Tufts University School of Medicine, and physician in the pulmonary and critical care division at Tufts Medical Center, to discuss what he thinks people should know about asthma. 

How do genetics impact breathing problems like asthma?

Jeremy Weinberger: There are certainly underlying genetic predispositions, but asthma is a complex disease. It’s not like others where if you have one mutation of a gene, you’re going to get the disease. There are varying traits and factors that influence diagnosis. 

Then there’s all the environmental things we’re around, whether it’s pollution, or whether someone is exposed to a bad respiratory viral illness that sets off an inflammatory cascade, all of which can lead to adult-onset asthma. There are many different life experiences that can contribute to airway inflammation and ultimately asthma. 
 

How does the environment, specifically air quality, impact our breathing?

This topic has been in the news a lot recently, specifically with the Canadian wildfire smoke and small particulates that it carries. There is concern that as the global temperature goes up, there are going to be more fires, more smog, longer allergy seasons, and reduced outdoor activity which can all impact asthma. It’s a huge public health issue, and from a socioeconomic standpoint, there’s a disproportionate effect on people who have less means. 

Those people may not have central air conditioners with high efficiency filters to help clean the air they breathe, or HEPA filters that are going to catch those small particulates. They’re also more likely to have worse ventilation for indoor cooking and gas stoves. All these exposures are cumulative, and the more you’re exposed to them in early life, the more likely you’ll deal with a cascade of health effects later down the road.
 

With such a complicated array of potential causes, as a clinician, how do you begin to work with a new patient who may be suffering from asthma?

Starting with the symptom side, I’ll ask a series of questions to understand the basic nature like:

• When is the last time your breathing felt normal or normal for you?
• Are you having cough, wheezing, shortness of breath?
• What time of day do the symptoms present?
• Is it worse at night?
• Are there situations/exposures where symptoms are worse? For example, when you are around a family pet?

These are all broader questions, but then I get into the weeds about exposures by asking questions such as:

• Where do you live?
• Is it a single-family home, apartment building, or college dorm?
• Do you have hardwood floors or carpet?
• Do you have central air conditioning?
• Do you use window air conditioning units?
• Do you change your filters?
• What type of bedding do you use? Is it down?
• Do you wash your bedding on high heat to try to kill dust mites?

These are the standardized questions I ask in my initial intake visit for a new patient that I’m seeing with asthma, whether it’s mild or severe. 

By asking these questions, I’m trying to pick up what can be teased out just from their history. Often for patients who have moderate to severe asthma, I will also send off a battery of blood tests for allergies. 

What can you tell about someone’s asthma diagnosis from their allergy test results?

As part of their diagnosis, some patients with allergic asthma will see an allergist for skin testing, where the skin is pricked and then exposed to certain environmental allergens, like animal dander, tree pollen, and dust mites. In pulmonary diagnoses, we more commonly order a blood test looking for allergen-specific IgEs, or immunoglobulin Es, where the “E” stands for epsilon heavy chains, which are defining characteristics of these specific antibodies. We pick up elevated IgE levels when we’re exposed to specific things in the environment, like cockroach and mouse urine, and different molds. I’ll combine those results with my intake questionnaire and other data to discuss my top recommendations in terms of treatment. 

For instance, if someone’s IgEs are elevated when they’re exposed to dust mites, I would recommend they get dust mite-impervious covers for their mattress and pillows, and wash their sheets weekly in the highest-temperature cycle available on their washing machine to kill dust mites. If someone has a pet that they love and can’t part with, I’ll recommend they keep the pet out of the bedroom, get rid of all the carpeting in the house, and install a HEPA filter in the home that can help with some of the dander.
 

What type of breathing tests will you do as part of your evaluation?

Almost all of the patients who make it to my clinic will have had spirometry, a non-invasive lung function test, done before their intake appointment. But it’s one of the tricky things with asthma: you can’t make the diagnosis based on spirometry alone. It really does come down to their history.

What concrete links are there between allergies and asthma?

The most common diagnosis in our clinic is Th2 asthma, which refers to the type of cells that are generated in response to different types of pathogens, or allergic responses. This is also the type of asthma that is typically associated with elevated IgEs and eosinophils. When those IgEs and eosinophils are in the blood, a downstream inflammatory cascade is generated that then leads to inflammation in the airways and asthma symptoms. 

For underlying genetic reasons, the body makes these antibodies and creates more inflammation, especially in young children who have eczema, food allergies, and reactions to different exposures over time. When the whole body generates inflammation, not only are you going to get some asthma-type symptoms, but you’re also more likely to be sensitized to other things. 

That reaction is what’s known as the allergic march, where once you’ve developed allergies, you’ll have ongoing inflammatory responses, and there is a lot of research happening into how we can disrupt or interrupt this allergic march for young kids with multiple sensitivities.

There is another type of asthma called Th1 asthma which is oftentimes associated with patients who are obese and less responsive to our typical medications, but we know less about the condition in general.

How common is it for someone to be misdiagnosed with asthma and why?

Chronic cough is often over-diagnosed as asthma, but there are actually three things that most commonly cause a chronic cough. One is what we call upper airway cough syndrome, which is just the fancy way of saying post-nasal drip, another is acid reflux or GERD mediated, and the third is asthma. 

The amount of time that I spend talking about people’s gastrointestinal history and acid reflux can surprise patients. They’ll wonder, “Why is this pulmonologist asking me about the latest time of day I consume caffeine?” and “Why does he want to know if I ever lay down right after having caffeinated beverages?” The answer is that at least 30% of people who make it to my clinic with cough and a preliminary diagnosis of asthma end up having something else. The most common something else is uncontrolled acid reflux, leading to some degree of subclinical aspiration of stomach content, which reaches the airways and can cause inflammation, cough, and can lead to a syndrome that looks a heck of a lot like asthma and can contribute to asthma worsening..

Stomach acid is caustic. The airways don’t like to be exposed to caustic things, so by exposing your airway to stomach acid, you can generate an inflammatory cascade that is going to lead to bronchial constriction and inflammation in the airways, which is basically what asthma is.

What types of medications are available to treat asthma?

From a pharmacological standpoint, there are two main classes of inhaler therapies. One is going to be what we call bronchodilators—broncho meaning airway, and dilators meaning to relax or open. Those are going to work by opening the airways more because one of the hallmarks of asthma is the airways become constricted and smaller during an episode. 

Then there’s the anti-inflammatory inhaler, which is an inhaled steroid. We think of steroids as having an impact like a bazooka used on the immune system. When you take them by mouth, they can be amazing medicines, but they also have a ton of side effects. When you inhale them, very little of the steroid gets absorbed by the body, instead staying in the airways to decrease inflammation. 

What would be a reason to prescribe one version or another?

It used to be that people with mild asthma would be on a medicine like albuterol, which is a short-acting bronchodilator or relaxer, but we are moving away from that treatment even in people who use only a rescue emergency inhaler. Instead, we’re prescribing a combination inhaler that contains both a steroid and a bronchodilator in it. That’s been a huge shift in asthma over the last couple of years.

If someone is on albuterol as their rescue inhaler, they should have a discussion with their primary care physician or pulmonologist about whether they should also be on an anti-inflammatory with that.

Are there any other types of medication someone with more severe asthma should be aware of?

Yes, there’s another class called biologic medicine for people whose asthma is not controlled by their inhalers, who continue to exacerbate and either end up in the hospital or need oral steroids, which again have all those side effects. These medications have really changed the landscape of more severe asthma.

They act more systemically and target different things in the blood, as well as different immune cells and immune mediators that live in the airways and the lining of the airways, called the airway epithelium. All of them target slightly different parts of the inflammatory cascade. 

Is there anything else people should know about asthma medications?

Increasing public awareness that just reaching for your albuterol inhaler is no longer a recommended approach is really helpful and sharing that information creates an opportunity for patients to advocate for themselves if they're on that regimen—especially if they're having trouble with their symptoms and with their asthma control. If that’s the case, they should talk to their primary care doctor or see a pulmonologist about getting to more guideline-based therapy with both an anti-inflammatory and some airway relaxer-bronchodilator approach.