A new study on severe asthma entitled “Phenotypes of severe asthma among children and adolescents in Brazil: a prospective study” was published in BMC Pulmonary Medicine by Wenderson Clay Correia de Andrade, first author, and Laura Maria de Lima Belizário Facury Lasmar, senior author, from the Graduate Program in Health Sciences and Pediatric Pulmonology Unit at Federal University of Minas Gerais in Brazil, along with colleagues. In this study, the research team showed that individuals with severe uncontrolled asthma should be re-examined frequently to decrease exacerbations and to identify patients with constant airflow limitation.

Asthma is a chronic lung disease characterized by inflammation and narrowing of the airways. The most frequent symptoms of asthma are frequent periods of wheezing, chest tightness, shortness of breath, and coughing. In low and middle-income developing countries, severe uncontrolled asthma is associated with excessive morbidity. Severe uncontrolled asthma includes untreated severe asthma, difficult-to-treat severe asthma and treatment-resistant severe asthma. Moreover, these patients with uncontrolled asthma are more prone to manifest adverse effects to asthma medications and to develop chronic morbidity, such as impaired pulmonary function as well children with this condition may have impaired lung growth.

The research team described the phenotypic characteristics of difficult-to-treat and treatment-resistant severe asthma in a group of children and adolescents in Brazil. They performed a prospective study between 2010 and 2014 that analyzed 61 patients aged between 6 and 18 years old with severe uncontrolled asthma. The pulmonary function, measured fractional exhaled nitric oxide and sputum cytology was analyzed in these samples. Among the 61 patients analyzed, 10 had been incorrectly diagnosed, i.e. without asthma, 15 and 36 had, respectively, moderate and severe asthma that was not controlled. The patients with severe asthma resistant to therapy had higher levels of exhaled nitric oxide and a lower forced expiratory volume, i.e. a measure of how much air a person can exhale during a forced breath, when compared with individuals with difficult-to-treat severe asthma.

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The authors concluded that it is difficult to distinguish individuals with treatment-resistant severe asthma from those with difficult-to-treat severe asthma. Therefore, the parameters reduced airflow and elevated exhaled nitric oxide could be used to distinguish these two clinical groups. Notably, individuals with severe asthma not controlled should be re-examined regularly to reduce exacerbations and identify impairment of airflow.