Meet the Expert
Farah Khan, MD, is a board-certified allergist/immunologist who treats pediatric and adult patients in private practice in Northern Virginia.
About 1 in 12 people in the U.S. have asthma. Sometimes, the condition causes only minor and intermittent issues. Other times, it becomes a persistent and serious problem, impacting one’s daily activities.
Asthma tends to become noticeable at a young age, though certain triggers can cause symptoms to crop up in adulthood as well. When a patient complains of shortness of breath, coughing fits, wheezing, or other symptoms, health providers run several tests to check for asthma and will do a thorough review of the patient's medical history to spot key risk factors.
If an individual does, in fact, have asthma, their provider can prescribe a quick-relief inhaler, long-acting corticosteroids, allergy medications or other therapeutics, based on your needs. The right medication can provide enormous and immediate symptom relief.
Farah Khan, MD, allergist and immunologist, shares what you need to know about how asthma is diagnosed and how proper treatment may improve one's life.
What are the signs that a person may have asthma?
Dr. Khan: Warning signs that people should pay attention to are wheezing, coughing, shortness of breath, and chest tightness when they are not sick. We can see this when kids are on a soccer field or playing with their friends in the backyard—they just can’t quite keep up and they have to stop to catch their breath.
If you’re waking up at nighttime with a cough, chest tightness, or shortness of breath when you’re not sick, those are big red flags. Sometimes we’ll see it when folks have a big laugh or a big cry which sets off a cough and shortness of breath.
For people who have environmental allergies, the upper airway is where those allergies assault your immune system. That is connected to your lower airway, which is where asthma comes into play. If your environmental allergies are poorly controlled and you have the genetic predisposition to developing asthma, it sets up the perfect storm to develop an asthma diagnosis.
What steps do doctors take when diagnosing asthma?
Dr. Khan: The first thing that we do is take a really detailed clinical history. If you ended up in the emergency room three times over the last six months because every time you got sick with a cold you needed nebulizers and steroids, that’s a red flag. Knowing your exercise tolerance is also important.
Then there are guidelines put out by the National Heart, Lung, and Blood Institute. We use those criteria to help us figure out how the patient’s potential diagnosis falls on the spectrum of asthma.
In terms of objectively diagnosing the condition, most of us have access to spirometry, which gives us an objective marker of lung function. It gives us a sense of how much air a patient can get in and out.
When we’re really concerned about a potential asthma diagnosis, we usually give the patient either an Albuterol inhaler or a nebulizer treatment. They take two puffs, and 15 to 20 minutes later you have them repeat that breathing test to see if there is any change. If there is something striking, then we usually label this as asthma and initiate a daily controller medication.
There’s also something called a FeNO—an exhaled nitric oxide test. If patients have a very particular type of allergy cell called eosinophils that are causing the inflammation leading to asthma, you can measure that. It’s just a snapshot of what your lungs are doing that day, but it gives us a sense of how bad the inflammation is and whether a patient is compliant with their inhalers.
We use all three of these—detailed history, spirometry, and exhaled nitric oxide test—to give us a sense of what this patient’s history is amounting to.
How often do misdiagnoses occur, and why does a proper diagnosis matter?
Dr. Khan: What I find overwhelmingly is that oftentimes primary care providers are hesitant to label their patients as having asthma.
Sometimes, the patient’s history is very consistent with somebody who has persistent asthma and needs to be labeled as such, but maybe their primary care provider has shied away from it. When patients come to us with that history—and their spirometry and breathing test are pretty impressive—we label them and get them started on therapy right away.
We see this more frequently from pediatricians. They have a hundred other things they’re doing in a well check or a sick visit, but then referring those patients to either pediatric pulmonologists or allergists so that we can evaluate those patients and get them started on therapy is really key.
In terms of misdiagnosis, one of the other big conditions that we see, especially in high achieving competitive people, is something called vocal cord dysfunction. Symptoms may mimic asthma, but it’s a completely different condition—it has to do with your vocal cords sort of snapping shut when you’re trying to take a big breath in and creates the perception of chest tightness and shortness of breath.
They can be mislabeled as asthma and get started on high doses of medications, but none of those medications end up really working for them. Months later, they’ll come in and be evaluated for environmental allergies or something and when we’re taking their history, it turns out that it’s really vocal cord dysfunction. We then need to start breathing exercises to retrain their vocal cords, potentially get them into speech therapy and off the asthma medications.
With the older population, we see chronic obstructive pulmonary disease, maybe because of an occupational substance that they were exposed to or due to their own smoking history. Therapies are similar to asthma, but there are a couple of other big differences in terms of medications and treatment for those patients. But most of the time, it’s not as misdiagnosed, and they seek care with pulmonologists.
How do you know when an asthma diagnosis is accurate?
Dr. Khan: What is remarkable about asthma therapy is that whatever inhaler you end up on, you start to notice a difference in your symptoms pretty quickly—usually within a few days and definitely by week three or four.
With patients who have vocal cord dysfunction who come in on high doses of Albuterol or inhaled steroids and it’s been six months, it’s a sign for me to pause and ask, “Why is this 17-year-old on all these high doses of inhaled steroid and still complaining of shortness of breath?”
The therapy should start to benefit patients pretty quickly and it should be a red flag for patients when it’s been a month or more, and they really haven’t had any relief in symptoms. It means something else might be going on.