Background: Viral infections can promote allergic sensitization in genetically susceptible individuals. Besides, they are the main cause of wheezing in children.
Objective: To assess the frequency with which influenza, parainfluenza, adenovirus and respiratory syncytial virus (RSV) cause rhinopharyngitis in patients with asthma and wheezing.
Patients and methods: Longitudinal, prospective study in which 168 patients with asthma and wheezing, who attended the outpatient allergy clinic of the National Institute of Pediatrics, Mexico, during the spring (from April through June), with clinical signs and symptoms of rhinopharyngitis were included. Samples of nasal secretions were taken with a long swab, and identification of RSV, adenovirus, infuenza A and B and parainfluenzae 1, 2 and 3 by means of direct immunofluorescence (DI) was carried out.
Results: Samples of nasal secretions were taken in 100 children with asthma and 68 with wheezing, aged 2-17 years. Viral identification was positive in 75% and 44.1% of the patients, respectively. By age group, RSV predominated among children in preschool age; and influenza A among children in school age and adolescents. Influenza A, adenovirus and parinfluenza 3 were identified more frequently in asthmatic children, whereas influenza A and RSV in patients with wheezing. Coinfection of two viruses was found in 17.1% of all patients with positive DI; the most frequent association was parainfluenza 1 and 2.
Conclusions: Viral identification by means of DI is a fast and non-invasive technique that could favor the early beginning of antiviral treatments in children with asthma and wheezing.