What’s That Wheeze? Identifying Asthma

Asthma is a chronic disease that affects 9% of children under 17 years of age—about 6.7 million children in the US. Every year, asthma accounts for 13 million missed school days, 200,000 hospitalizations, and 750,000 visits to emergency departments. Chances are, you either have a child with asthma, or you know someone who does.

I recently wrote a post on my Facebook page asking parents what questions they had about asthma. I wasn’t surprised to see the stream of questions that followed, especially given that asthma is such a common disease. It’s not just parents, though; asthma is often misunderstood, misdiagnosed, and mismanaged by doctors. The current guidelines for diagnosing and treating asthma in children are 74 pages long–and they’re written for people who should already have at least a basic level of knowledge. I can’t possible cover every possible question about asthma, but hopefully, I can address some of the big ones.

What is asthma?

Let’s start by thinking about the lungs as an upside-down tree, with the trachea (or windpipe) as the trunk. The trachea divides to direct air into both lungs, and then branches into smaller and smaller airways to reach the microscopic sacs in the lungs where oxygen enters the blood.

Asthma is a disease caused by over-reactivity of these small airways, which causes the airway walls to contract. At the same time, these walls become swollen and begin to produce more mucus. This combination of factors takes tiny airways and makes them even smaller. As these airways shrink, it becomes difficult for air to get where it needs to go, and even harder for it to get back out. It’s a bit like trying to drink a smoothie through a coffee stirrer.

The outside observer may notice coughing, wheezing, and faster or more difficult breathing; people experiencing asthma symptoms feel chest tightness, shortness of breath, or a feeling of drowning. I’ve been there myself, and it’s not pleasant.

What is wheezing?

As the small airways in the lungs get even smaller, the air traveling through them begins to cause vibrations, just as it does with musical instruments. With a stethoscope, this noise sounds like a high-pitched, musical sound (a bit like a harmonica), heard mainly as the child is breathing out. In severe cases, when the airways close down so much that very little air is moving through them, this noise can go away completely; the lack of wheezing is not necessarily a good sign.

It’s important to realize that not all children with asthma wheeze, and not all children that wheeze have asthma. Wheezing is just one clue as to what may be going on, and cough is actually a more common (but similarly non-specific) symptom.

And as a side note, those Darth Vader noises coming from the snotty toddler across the room are probably not wheezing. Most true wheezing can be heard only with a stethoscope.

Is it asthma?

One of the most difficult questions about asthma is whether a particular child has it. You’d think that we could nail this diagnosis, since most pediatricians see it on a daily basis. But the problem—especially in very young children—is that there are a lot of other things that can look like asthma. And while there’s no minimum age at which asthma can be diagnosed, the lines can be pretty blurry for the first few years.

Many other conditions can cause cough, wheezing, rapid or labored breathing, or shortness of breath. Viral infections in young children will often cause wheezing, which isn’t necessarily related to asthma and may not respond to asthma treatments. Pneumonia can be difficult to distinguish from asthma symptoms, especially since the two are not mutually exclusive. A foreign body in the airway (not altogether uncommon in kids who put everything in their mouths) can cause wheezing and labored breathing. Serious conditions like anaphylaxis, heart failure or cystic fibrosis are sometimes misdiagnosed as asthma. Allergies, anatomic problems with the airway, vocal cord dysfunction, and plain-old deconditioning (like trying to run for the first time in years) can all overlap with asthma symptoms.

I could go on, but you get the point—diagnosing asthma is not always straightforward. There’s no blood test or imaging study that can say whether or not a child has asthma; what we are really looking for is a pattern. If a child has cough and wheezing caused by typical asthma triggers, struggles with allergies and eczema (which are frequently found with asthma), has multiple family members with asthma, and improves with asthma treatment, it’s a pretty easy call. If they’re developmentally able to cooperate with lung function testing (usually around 4-6 years of age), that information can help. Take a few of those factors away, and it’s a little less clear.

While it’s frustrating to parents for doctors to dance around this diagnosis, we are–for better or worse–hesitant to label kids prematurely. The confusing limbo of diagnoses like “reactive airway disease” or “viral-induced wheezing” often leaves parents wondering: “Is it, or isn’t it?” In many cases, we should just go ahead and call it what it is. But in many others, kids are over-diagnosed and over-treated. It’s tough to be perfect.

Is asthma inherited?

The simple answer is yes…sort of. Children with one or two parents who have asthma, allergies, or eczema are more likely to get these conditions themselves. But it doesn’t always happen. This is an area of ongoing research, but the current theory is that while children may be born genetically susceptible to asthma, it takes exposure to certain triggers to cause the disease. So yes, it may be partially your fault that your child develops asthma…but you gave them your brains and good looks, too, so we’ll call it even.

How is asthma related to other conditions?

There are a variety of conditions that tend to go along with asthma. Two very common examples are allergic rhinitis (allergies) and eczema, which occur frequently in children with asthma. These conditions are interrelated; in many ways, they are simply different parts of the body reacting in the same way. Other conditions associated with asthma are gastroesophageal reflux, sleep apnea, vitamin D deficiency, and obesity. One of the keys to good asthma management is looking for these conditions and treating them if they are found. In many cases, addressing these issues will improve asthma symptoms as well.

A relationship between food allergies and asthma hasn’t been solidly established. Food allergies don’t typically cause asthma symptoms directly, but both of these conditions are more likely to be found in children who have a tendency towards allergic reactions. If your child has cough or difficulty breathing immediately after ingesting food, consider the possibility of anaphylaxis (a life-threatening allergic reaction that demands emergent attention).

Another common condition related to asthma is RSV infection during infancy. This virus causes a disease called bronchiolitis, and children who get it are at higher risk to develop asthma when they are older. Whether RSV plays a role in causing asthma or simply causes more noticeable symptoms in children with sensitive airways is tough to sort out.

When should I have my child evaluated?

If you’re concerned that your child is breathing too fast or too hard, having difficulty catching his breath, or having other severe symptoms, he deserves urgent medical attention. Whether you seek care at your pediatrician’s office or the emergency room depends on the severity of the symptoms. For symptoms that are less urgent, like a frequent cough or difficulty with exercise, schedule a visit with your pediatrician. But remember, I can’t see your kids (unless they happen to be my patients), so I can’t give you advice for your specific situation. As a general rule, any concerns you have about your child’s health are worth discussing with your doctor.

The good news about asthma is that, while we can’t make it go away completely, we can control the symptoms and allow even children with severe asthma to live very normal lives. The first step to effectively treating asthma is knowing what you’re dealing with. The next step is learning what to do about it–more on that in my next post.