Wheezy illness in children < 2 years old.
Being a child.
RSV (mostly), parainfluenza 1 and 3 viruses, adenoviruses, rhinoviruses, and M. pneumoniae.
See your pediatrician, I am an internist. But steroids do not help (PubMed).
ICD9 Codes (Soon to be supplanted by ICD10)
Bronchiolitis (acute) (infectious) (subacute) 466.19; with bronchospasm or obstruction 466.19; influenzal 487.1; respiratory syncytial virus 466.11.