Severe asthma in children

Most childhood asthma is mild/moderate and is easily controlled with regular use of inhaled corticosteroids (ICS) and rescue bronchodilators. However, between 5% and 10% of children will have asthma that remains difficult to control despite high doses of appropriate asthma therapies. Children with ‘difficult to control’ asthma are responsible for a substantial proportion of the morbidity and health care costs associated with asthma. The recognition that not all ‘difficult to control’ asthma is ‘severe’ is perhaps the most important message for paediatricians looking after children with such asthma. Before labelling asthma as ‘severe’, factors that might make asthma difficult to control need to be identified and addressed. In the small number with genuinely severe asthma, there are a number of different subgroups or ‘phenotypes’. In the future, clearer definition of phenotypes is likely to lead to better targeting of therapy and to improved asthma control.