Difficult asthma in adults: recognition and approaches to management.
Difficult asthma must be distinguished from severe asthma. It is then important in patients with suspected difficult asthma to ensure that the diagnosis is correct, and that if the patient has asthma that the attributed symptoms are indeed all genuinely due to the asthma and not to coexisting physical or psychogenic respiratory conditions. It is also important to be alert when there is discordance between symptoms and objective lung function in order to recognize both poor perceivers and over-reactors. Difficult asthma can occur in patients with objectively mild, moderate or severe disease, but the consequences are most dramatic in patients with severe asthma. Asthma may be difficult for the patient, for the clinician or both because of disease factors, doctor or nurse therapist factors, and/or patient factors. Investigation requires access to the full range of respiratory, imaging and allergy tests. It also requires a multidisciplinary approach involving ear, nose and throat specialists and speech therapists, and access to psychiatric and psychological assessment and therapies. Poor compliance is associated with significantly poorer asthma and asthma-related health outcomes. Poor compliance can be recognized in two-thirds of such patients by their not attending scheduled appointments. Poor compliance is significantly associated with anxiety, social deprivation and adverse family circumstances, and these characteristics and adversities probably contribute to the poorly compliant behaviour. In difficult asthma it is important to identify and manage the condition causing the symptoms rather than prescribing more and more asthma therapy. Recognizing psychosocial adversity is essential. A structured approach is essential. There remains a small number of patients with genuine steroid-resistant asthma, some with predominately neutrophilic rather than eosinophilic airway inflammation, and others for whom the secondary gain of continuing symptoms is overwhelming. There is a need for further research using agreed definitions, structured approaches and a full range of investigations in patients with difficult asthma.