The term difficult asthma generally refers to individuals that are prescribed high doses of asthma therapy, and yet still have uncontrolled symptoms. This can be for a number of reasons; they might have suboptimal therapy, or confounding conditions that affect asthma control. Of course, they could also have truly severe asthma which is not responsive to treatment.

Healthcare professionals should always consider poor adherence to maintenance therapy before escalating treatment in patients with difficult asthma

The challenge is differentiating between difficult asthma and truly severe asthma. Difficult asthma includes asthma that is uncontrolled due to poor adherence, poor inhaler technique, environmental triggers or confounding conditions. Patients whose asthma control improves rapidly with correction of such problems do not have truly severe asthma.

The systematic evaluation of patient with difficult asthma should include:

• confirmation of the diagnosis of asthma
• determine severity of disease (based on treatment requirements from the previous year)
• determine level of asthma control
• assessment of adherence to therapy