UK scientists say they have found a new cause behind much of the damage asthma causes.
Cells lining the airways are squeezed to destruction during an attack, their research shows.
And drugs to prevent this, rather than manage its aftermath, might break the cycle of harm, the Kings College London researchers told the Science journal.
The airways of people with asthma are sensitive to triggers such as pollen, pets and exercise.
They become inflamed or swollen, causing symptoms including coughing, wheezing and breathlessness.
Existing drugs or inhalers can reduce this inflammation and help keep the airways open.
But repeated attacks can cause permanent scarring and narrowing of the airways.
During an attack, the smooth muscle surrounding the airways starts to squeeze and tighten, known as bronchoconstriction.
The Kings College London team studied this process in detail, using mice and human lung-tissue samples.
Lead researcher Prof Jody Rosenblatt said bronchoconstriction damaged the airway lining, resulting in long-term inflammation, wound healing, and infections that cause more attacks.
Until now, this lining damage had been overlooked, she told BBC News.
“This epithelial lining is the body’s first line of defense against things like infections and yet it is getting damaged during asthma attacks,” Prof Rosenblatt said.
“There’s this constant wounding going on – it’s a vicious cycle.
“If we can block the damage, we are hoping that might stop attacks from happening at all.”
