Our lungs are made up of millions of tiny airways or bronchial tubes.  It’s in these tiny airways that oxygen from the air we breathe is able to get into our blood.  The bloodstream then brings the oxygen to all the cells in our body.  Anything that makes it harder for air to get into the lungs makes it hard to breathe.

With asthma, these airways get blocked.  This happens in three main ways:

1) Swelling of the airways, called “inflammation”.

2) Airways get squeezed shut, called “bronchoconstriction”

3) Airways get plugged up with mucus.

Swelling (inflammation)
There is swelling or “inflammation” inside the airways.  The swelling takes up some space where the air used to flow.  So the airways are smaller.  Usually the swelling happens slowly, over weeks or months.

For people who have persistent asthma, swelling of the airways is the most important thing causing the airways to be smaller.  In these people, this swelling in the lungs is always there.  The swelling is there even when these people feel that they don’t have asthma and are breathing well.  But even if you can’t feel it, the swelling is the key to asthma.  Even a little bit of swelling makes the bronchial tubes sensitive (called “hyper-sensitivity”).  Sensitive lungs can get more swollen very easily.  And every time the lungs swell up a little, it becomes easier to swell up even more.  Sensitive lungs also get squeezed shut (bronchoconstriction) more easily.  It takes less of a trigger to cause an attack in sensitive lungs. 

If the swelling is not controlled well, then the asthma can not be controlled well.  There are certain medicines that help keep the swelling down.

Squeezing (bronchoconstriction)
All lung airways have little muscles wrapped around them.  During an asthma attack, these tiny muscles get tighter, and squeeze the airways closed.  So the airways are smaller.  This is known as “bronchoconstriction”.  Bronchoconstriction usually happens fast.  Usually when the airways get tight, people with asthma have some trouble breathing.  That is also when you can hear your child wheezing or your child might tell you that his or her chest feels tight inside.

There are medicines that relax the tightened muscles so that the airways can open back up.  When the airways open up, breathing gets easier.

MUCOUS PLUGGING

A little bit of mucus is always made inside everyone’s airways.  With asthma, more mucus is made.  Also, the mucus that is made is thicker than regular mucus.  If the airways are already small from inflammation and bronchoconstriction, the extra mucus can plug up the airways even more.  If airways get plugged with mucus, air can’t go in or out and breathing gets harder.  Many children with asthma will sometimes cough up some mucus.  Sometimes it feels like mucus is “rattling” around in the chest, but the child can’t cough it out.

There is no good medicine to make mucus in the chest go away.  The asthma medicines for inflammation help people with asthma make less mucus.  Other medicines open up the airways.  When the airways are open, kids can now cough out the extra mucus.  It is very unusual for young kids to be able to “spit out” or “cough up” the mucus in their lungs.  Usually, they cough up and swallow the extra mucus.  Sometimes swallowing mucus can cause an upset stomach or even make children throw up.  But it is better to swallow the mucus than have it stay in the lungs.