Clinical utility of diagnostic methods in respiratory allergy in pediatric patients.

Respiratory allergy is a single condition which affects upper and lower airways. The diagnose in childhood is essential to prevent the allergy respiratory progression. We aimed to analyze the clinical utility of diagnostic tests to identify rhinitis phenotypes and to differentiate between atopy and respiratory allergy in children. 173 children with a clinical suspicion of allergic rhinitis were prospectively evaluated in our pediatric allergist service. The allergological study included clinical history, physical examination, specific IgE (sIgE), skin prick test (SPT), and nasal allergen challenge (NAC). It identified 4 phenotypes: i) allergic rhinitis (AR): positive NAC, SPT and/or sIgE, ii) local allergic rhinitis (LAR): positive NAC and negative SPT and sIgE, iii) dual allergic rhinitis (DAR): positive NAC to perennial & seasonal allergens, SPT and/or sIgE to seasonal and negative to perennial allergens, and iv) non-allergic rhinitis (NAR): negative study. Most of children were girls, with a family history of rhinitis, non-smokers and an urban habit. The mean age of onset of symptoms was 10 (3.982) years. 45,7% had a diagnosis of AR, 24,9% LAR, 11,6% DAR and 17,9% NAR. Atopy was detected by SPT in 57.3%, by sIgE (54.9%), no patient with negative SPT had positive sIgE. However, 36.5% of allergic patients were not correctly classified by these tests being diagnosed by clinical history+NAC. Clinical history and NAC were the most useful diagnostic methods for correctly diagnose respiratory allergy in children. sIgE did not improve the detection of atopy obtained by SPT, and could be avoided as atopy screening-test.