The approach to a child with severe asthma

Abstract

Severe asthma is considered a complex and heterogeneous disease, which includes different phenotypes, defined in terms of both clinical and molecular characteristics and underlining endotypes. It is estimated that severe asthma affects 2-5% of all children with asthma. It occurs more frequently in children older than ten years of age, with a slight prevalence among the male sex. Although severe asthma is uncommon, this group of children has an increased risk of drug side effects and life-threatening exacerbations that impair quality of life. Also, the financial burden from medication, scheduled and unscheduled doctor visits, hospitalizations and absence from school and work by parents have to be considered. There is no uniform definition of severe asthma, but the common characteristic is the need for maximal maintenance therapy, including high-dose inhaled steroids, long-acting beta-agonists, and/ or leukotriene receptor antagonists/theophylline. Despite the highest doses of maintenance therapy, patients with severe asthma fail to control the disease. Uncontrolled asthma has to be re-evaluated by confirming the diagnosis and modifying factors contribut- ing to symptoms and exacerbations like poor adherence, environmental risks (persistent allergen and pollutant exposure) and co- morbidities (upper airway disease, gastroesophageal reflux, obesity, anxiety). Children with poor asthma control due to misdiagnosed asthma, poor adherence or environmental risks have difficult-to-treat asthma, whereas children who still have poor control despite re-education to improve adherence and modification of environmen- tal risks have severe, therapy-resistant asthma. The approach to children with difficult-to-treat-asthma, which includes systematic evaluation and acting on modifying factors, enables achieving the long-term goals of asthma treatment in approximately two-thirds of patients. The remaining children, whose asthma is still uncontrolled despite optimized therapy, have severe, therapy-resistant asthma. Those children are candidates for bio- logical treatment based on the determination of phenotypic features.