What is wheezing, anyway?

May 14, 2010  |  General

The traffic analysis of this blog tells me that wheezing — what causes it and what we do about it — is one of the most common search terms that bring people here. It’s a common problem, and I’ve written some about it before. The fact that so many people are searching for information about it tells me that doctors may not be doing a great job in explaining what it is. This post will tell you what a doctor means by the word.

“Wheezing” is one of those words which, when commonly used by non-physicians means one thing (noisy breathing), but which means something else when doctors use it. So, when a doctor tells you your child is wheezing, what is she telling you? To understand that you need to know a little about the anatomy of the lungs.

The lungs are made up of two main components: tiny air sacs (called aveoli), where the business of getting oxygen into the blood stream happens, and the pipes that conduct the air down to the air sacs. This system of pipes begins with the largest of them – the windpipe (called the trachea) – in the throat. It ends with the tiniest of them – called the bronchioles – which are just before the air sacs. Think of the system as an immense tree: the trunk, branches, and twigs are the pipes, and the leaves are the air sacs. Here is a picture.

Wheezing is the noise that happens when the small airways have something blocking them. The blockage most commonly comes from constriction of the airways, but sometimes it may be from debris, such as mucus, obstructing the passage. The sound of air flowing past these choke points in the small airways makes a whistling sound – that is a wheeze. Most of the time it is a sound heard when a child breathes out, not in, because it’s more difficult to get air out than in so that’s when the problem is obvious.

We can hear wheezes with a stethoscope, but sometimes they are so obvious we don’t need one. A more subtle sign of wheezing is when a child takes more time to get air out with each breath than he does to breathe air in.

How do we treat wheezing? Since the most common cause is constriction of the small airways, we typically give inhaled medications to reverse the constriction.

Bottom line: when a doctor uses the word wheeze, we aren’t just describing noisy breathing. We mean a specific thing that has a specific treatment.


  1. Thanks for this information. My 2 year old toddler has had a couple of times what i thought is wheezing.

    I hope my toddler wouldnt have the third round of this ‘sound’ but if it comes again, i will pay special attention whether the sound is from breathing-in or breathing-out. But i must say it is pretty scary as i was totally helpless when it happened.

    Just to share, and hope you can further comment based on your experience, on the severity of this. Right before my toddler had this heavy breathing, she starts with some initial coughs (as if she tried to clear her throat or airway), followed by a need to drink lots of water and, after that, thats when the breathing sound starts and my toddler gets scared herself too. The breathing sound lasted about 7 minutes before my toddler calms down to sleep. By the time we got to the doctor, she is fine.

    What would you say of this?

  2. Hi Jamie:

    It’s hard to say what that is without evaluating your child and I can’t give you specific medical advice over the interent, but I would wonder about a couple things. It can be hard to tell the breathing abnormality of croup from that of wheezing, especially after the fact. Wheezing does often have a strong component of cough with it. Both conditions can come and go fairly quickly. But infectious croup, the kind that viruses cause, doesn’t generally improve that fast.

    There are some other airway problems that come to mind. One is called spasmodic croup; it can come and go that fast. Another is called laryngeal or tracheal malacia (so-called “floppy airways”), although children with breathing problems from that condition are generally infants, not toddlers, and the breathing problem doesn’t generally come and go that fast. It also tends to be a chronic problem.

    At any rate, the expert doctors on these sorts of airway issues are the pediatric pulmonologists (lung specialists). If the problem continues, I’d consider consulting one of those if you can. My second choice would be a pediatric allergist — even though your child’s problem doesn’t sound like an allergy to me, the pediatric allergists are also quite good at airway problems generally. Perhaps your child’s regular doctor could refer you to one of those.

    I hope this helps, and thanks for stopping by.

  3. Hi I wanna my.daughter is 2yrs old and she keeps wheezing no fever just cough andwhezzing what.can I do

  4. Take her to your doctor for evaluation. I can’t give you specific medical advice over the internet because I’m not your child’s doctor.

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