Family history of atopy and clinical course of RSV infection in ambulatory and hospitalized infants.

Respiratory syncytial virus (RSV) infection can be severe in pediatric patients. Risk factors for severe disease include age less than 6 months, prematurity, preexisting heart or lung disease or malformations, gastroesophageal reflux, and immunodeficiency. The aim of the present study was to investigate the influence of family history of allergy on the clinical course of RSV infection in ambulatory and hospitalized infants. In a retrospective study, 172 patients younger than 12 months of age (99 inpatients and 73 outpatients) were enrolled. Information was obtained from hospital charts and from questionnaires sent to pediatricians. Inpatients had a significantly higher rate of atopy in their family history than outpatients, 62% and 29%, respectively (P < 0.001). Bronchiolitis was diagnosed more frequently in patients with an atopic burden than those without, 89% versus 74%, respectively (P < 0.02). Inpatients with an atopic family history had a significantly longer hospital stay than those without such a history, 7.4 +/- 3.7 days and 6.1 +/- 2.3 days, respectively (P < 0.04). Factors other than age that are considered a risk for severe infection with RSV (prematurity, preexisting heart or lung disease or malformation, and gastroesophageal reflux) were not confirmed in the present study. We conclude that infants with a family history of atopy are at increased risk for severe RSV infection as indicated by higher rates of hospitalization, longer hospital stay, and more frequent occurrence of bronchiolitis. Copyright 2000 Wiley-Liss, Inc.