The report by Thomas et al¹ of patients whose symptoms masquerade as asthma is to be welcomed, although it is not clear how the authors selected their patients from all those referred to their clinic with "true" steroid resistant asthma. In addition, the opportunity has not been taken to determine what proportion of these patients would have fulfilled the criteria for type 1 brittle asthma. In a recent review of brittle asthma² I discussed, along with one of the authors of this report, factors such as gastro-oesophageal reflux, psychosocial aspects, sleep apnoea, and hyperventilation/vocal cord adduction as contributory or coincident factors, and in that review we put in a plea for future studies to try to characterise phenotypically patients at the severe end of the spectrum compared with other phenotypes or genotypes.

In our patients with brittle asthma hyperventilation is common and I agree that it can be difficult to . . . [Full text of this article]