Inhaled Corticosteroid Therapy in Newly Detected Mild Asthma

Inhaled corticosteroids are the most effective medications currently available to treat symptomatic asthma, and are free of clinically relevant unwanted effects, when used at the doses needed to provide optimal control in most patients with asthma. Inhaled corticosteroids also improve the physiological abnormalities of variable airflow obstruction and airway hyperresponsiveness that characterise asthma. Inhaled corticosteroids are also cost-beneficial when compared with other treatments, even in patients with milder asthma who are treated in primary care. For these reasons, inhaled corticosteroids are now being considered as first-line therapy for patients with regular daily asthma symptoms. Inhaled corticosteroids are, however, often not utilised until other treatments have been demonstrated not to provide optimal asthma control. Available evidence from both children and adults with asthma suggests that the benefits achieved from inhaled corticosteroids are reduced when their introduction as therapy is delayed for several years after persistent symptoms develop. For this reason, corticosteroids should be started soon after a diagnosis is made and persistent symptoms develop. It is not yet known, however, whether inhaled corticosteroids should be used in asthmatic patients who have very mild and infrequent symptoms and who have normal airway calibre most of the time. The current consensus statements do not recommend regular treatment in such patients. Airway biopsies from these asthmatic patients do show evidence of airway inflammation and structural changes; however, we do not yet know whether they lose lung function more rapidly than individuals without asthma, or whether the morbidity associated with very mild asthma warrants the use of regular treatment. This issue is being addressed in a large, multinational, placebo-controlled trial. The results of this study (available in 3 more years) will resolve this persisting question about inhaled corticosteroid use in mild asthma.