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.