Respiratory ailment (6)
'respiratory ailment' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for asthma that I've seen before include "Distressing breathing condition" , "Breathing problem" , "Distressing ailment affecting breathing" , "Common breathing ailment" , "Chest disorder" .)
(Other definitions for bronchitis that I've seen before include "Result of infection in respiratory tract" , "Chest illness" , "Respiratory disorder" .)