Why are hospital admissions of children with acute asthma increasing?

The hospital admission rate for asthma has increased in many countries. Particularly prominent has been the increase for children, especially male children under five yrs. The increased admission rate refers to increased number of individuals and to increased frequency per individual. The moderate increase in asthma prevalence does not account for the large increase in admissions. Various other factors are discussed here, such as changes in admission criteria, medical management, and/or clinical expression of the disease.