Box 1.

Coexistent conditions that can cause persistent ‘asthma-like’ symptoms, from case series of difficult asthma. Reproduced with permission.

< Dysfunctional breathlessness

< Vocal cord dysfunction

< Hyperventilation with panic attacks

< Obesity/physical deconditioning

< Chronic obstructive pulmonary disease

< Bronchiolitis obliterans

< Cardiac disease – congestive heart failure, cardiomyopathy

< Pulmonary vascular disease

< Bronchiectasis/cystic fibrosis

< Immunodeficiency

< Hypersensitivity pneumonitis

< Allergic bronchopulmonary aspergillosis

< Hypereosinophilic syndromes/Churg–Strauss syndrome

< Acquired tracheobronchomalacia