Similarities and discrepancies between exacerbations of asthma and chronic obstructive pulmonary disease.

Asthma is a chronic inflammatory disorder ofthe airways which causes recurrent episodes ofwheezing, breathlessness, chest tightness, andcough, symptoms which are usually associatedwith reversible airflow limitation.1 2 This definitionincludes the recurrence of respiratorysymptoms which might be otherwise classifiedas asthma exacerbations. However, the termasthma exacerbation is usually reserved formore severe and/or more persistent respiratorysymptoms requiring a prolonged increase ofcurrent antiasthma medication.1 2 Chronic obstructivepulmonary disease (COPD) is definedas a progressive airflow limitation, mostlyirreversible.3 4 The term COPD includes patientswith obstructive chronic bronchitisand/or pulmonary emphysema.3 4 Patients withmoderate or severe persistent asthma may alsohave an irreversible component of airflow limitation,and thus they may also be included inthe definition of COPD.3 The definition ofCOPD does not include exacerbations,3–5 evenif exacerbations are the main cause of medicalintervention and admission to hospital in thesepatients.