Derek Burnett
Derek Burnett is a Contributing Writer at Bottom Line Personal, where he writes frequently on health and wellness. He is also a contributing editor with Reader’s Digest magazine.
You likely know someone with asthma and are familiar with the wheezing and shortness of breath that come with an asthma attack. You might even be aware of some of the triggers that bring on such symptoms. But what is the medical science behind asthma? Why are some people put in danger by stimuli that most of us are able to withstand without issue?
Depending on the severity of the case, people with asthma may not experience any symptoms when they’re not suffering from an attack. During a flare, the primary symptoms are shortness of breath, coughing, wheezing, and tightness in the chest. Of course, these symptoms are not unique to asthma and may be present in respiratory infections or just in the temporary presence of a noxious substance that irritates the airway. And the same person with asthma might not always experience the same set of symptoms in the same way.
What’s happening inside the body during an asthma flare-up is that the muscles of the airway tighten and narrow, restricting the passage of air. This was once thought to be the sole physiological feature of the disease, but research has shown that asthma is also very much an inflammatory illness. At the same time the airway muscles are constricting, the immune system releases inflammatory substances that contribute to the restriction and narrowing of the bronchial tubes. These processes also generate excessive mucus, which further blocks the airway.
Asthma may first present during childhood or adulthood (it’s not unusual for people to outgrow childhood asthma). The disease may either be intermittent (meaning it comes and goes) or persistent, meaning the patient experiences frequent attacks. Whether intermittent or persistent, it is also classified as mild, moderate, or severe depending on the extent to which attacks disrupt the person’s activities.
Unfortunately, people with severe, persistent asthma are never really free of inflammation, even in the absence of an attack. There is a constant low level of inflammation in the airway, which makes the bronchial tubes overresponsive to irritants. And just as chronic inflammation can cause permanent physical changes to blood vessels in people with heart disease, the same is true of living with constant inflammation of the airways. Over time, scar tissue builds up and the airways become measurably thicker. Thicker airways restrict air flow, making it harder to breathe while causing yet more inflammation, in a negative feedback loop.
Because asthma’s symptoms are not unique to the condition, getting a diagnosis involves taking a complete medical history as well as measuring airflow in the lungs using an instrument called a spirometer. The doctor may also want to see a chest x-ray and perhaps the results of allergy testing, since asthma is often related to allergies.
Substances or phenomena that bring on an asthma attack are known as triggers. Common triggers include dust mites, mold, tobacco smoke, pet dander, chemical fumes, air pollution, and exercise. A person’s asthma triggers may be highly idiosyncratic. Two people with asthma could be exposed to the same air and only one of them suffer an attack. Most people who live with asthma for a while become familiar with their own triggers and learn to avoid them. And some people are more immediately sensitive to their triggers than others. Slow responders may not have an attack until hours or even days after being exposed to a trigger.
There appears to be a genetic component to asthma. We know that, as with allergies, it tends to run in families. People whose asthma is allergic in nature often have other allergies and sensitivities because their immune systems are prone to target benign substances as threats worthy of a robust response.
Scientists think some people develop asthma because of exposure to harmful substances such as air pollution during childhood before the immune system is completely developed. And experiencing certain respiratory diseases…especially RSV…at an early age may also cause lung damage that puts children at greater risk of developing asthma.
Asthma has no cure. Instead, patients and physicians work together to manage the disease. Fortunately, even most people with persistent, severe asthma can live normal lives (including participating in athletics) by using a good asthma-control plan.
An asthma-control plan consists of four main elements:
Avoiding triggers is a simple enough concept, even if it’s difficult to do in practice. You can’t always predict what stimuli you might be exposed to when you leave the house, but being aware of your triggers can go a long way toward helping you control your environment.
Most medications for controlling asthma work by dampening the inflammatory response in some fashion. Such medications include:
