Analysis of the flow-volume curve in children and adolescents with allergic rhinitis without asthma.

INTRODUCTION: There is epidemiological, functional and pathologic evidence that relates upper and lower airways, clinically known as a single respiratory tract. Patients with allergic rhinitis without asthma may present subclinical abnormal spirometry parameters. OBJECTIVES: To describe the results of the flow-volume curve in a group of patients with allergic rhinitis without asthma and analyze the possible associations between anthropometric, clinical and biochemical outcome measures with abnormal spirometry results. POPULATION AND METHODS: Observational, descriptive study including children and adolescents aged 6 to 18 years old with symptoms of allergic rhinitis without asthma. Age, gender, body mass index and duration of rhinitis were determined as per the subject's medical record. Allergen skin tests, flow-volume curve spirometry, determination of eosinophil count in blood and in nasal secretions, and total serum IgE were performed. RESULTS: A total of 84 patients were studied; 21 (25%; 95% CI: 15.1-34.8) presented at least one altered spirometry outcome measure. The FEV1/FVC ratio was the most affected outcome measure (10/84; 12%; 95% CI: 4.3-19.4). The multiple logistic regression analysis determined that spirometry alterations were associated with the number of blood eosinophils (OR: 1.00229; 95% CI: 1.00022-1.00436; p= 0.03) and the body mass index (OR: 1.31282; 95% CI: 1.08611-1.58685; p= 0.0049). CONCLUSIONS: Our results showed spirometry alterations in a considerable percentage of children and adolescents with allergic rhinitis without asthma. The blood eosinophil count and the body mass index could be associated with a sub-clinical alteration of pulmonary function.