Long-term effectiveness of a staged assessment for paediatric problematic severe asthma.

The recently proposed term ‘‘problematic severe asthma’’ (PSA) [1] describes children with persistent symptoms and/or severe exacerbations despite high dose treatment [2]. They suffer significant morbidity and consume a disproportionate amount of healthcare resources. Children with PSA are heterogeneous with respect to lung function [3] and asthma phenotype [4] and warrant careful evaluation. PSA [5] encompasses 1) wrong diagnosis; 2) significant comorbidities; 3) difficult asthma with potentially reversible factors such as poor inhaler technique, ongoing allergen exposure or poor adherence to treatment [6]; and 4) severe therapy-resistant asthma (STRA) that is refractory to maximal treatment despite optimised standard management [7].