Difficult/therapy-resistant asthma: the need for an integrated approach to define clinical phenotypes, evaluate risk factors, understand pathophysiology and find novel therapies. ERS Task Force on Difficult/Therapy-Resistant Asthma. European Respiratory Society.

A Task Force supported by the European Respiratory Society was set up in 1997 in order to address the major issues relevant to difficult/therapy-resistant asthma. Although the group of patients involved is small in comparison to the high numbers of patients with asthma, these patients consume a significant proportion of medical resources in terms of both time and money [1]. The major issues facing the Task Force were how to define "difficult asthma", how the patient with difficult asthma should be evaluated, the pathophysiological mechanisms underlying difficult asthma and the treatments available. The Task Force also concerned itself with defining the areas of research necessary to bring about a greater understanding of the causes of difficult asthma and novel treatments. The document resulting from this Task Force represents a consensus of different opinions, which will form the basis for further research.