If your baby has an acute asthma attack, the lining of his airways will become even more inflamed and produce more mucus. Then the muscles around his airways will tighten and his breathing tubes will narrow. He may breathe rapidly, cough, or wheeze (make a whistling sound) as his breath is forced through the narrowed airways. You may notice your baby's nostrils flare or the skin around his ribs suck in with each breath.
If left untreated or there's a delay in seeking medical attention, an asthma attack can be deadly. As soon as you notice any symptoms of an attack, promptly give your baby the "quick-reliever" medicine prescribed by his doctor. (If you don't have any emergency medicine, call 911 or take your baby to the closest emergency department.)