Currently, systemic corticosteroid treatment is considered themost effective medication for control of chronic asthma andrescue of acute exacerbation. Children can have poorly controlled asthma for numerous reasons. It is important to identify the underlying causes that contribute to poorly controlled asthma in each patient so that management strategies can be personalized to achieve the best outcomes. We have identified a biological basis for poor corticosteroid treatment response that can be used to distinguish a subgroup of children with asthma who respond poorly to treatment. nasal Periostin,SerpinB2 and CLCA1Gene expression might be a clinicallyuseful biomarker to identify a subset of children with difficult to-treat asthma with a biologic cause for poor corticosteroid response. Targeting Periostin,SerpinB2 and CLCA1 pathways in this subset might be a useful therapeutic strategy to enhance corticosteroid response.