Recurrent croup is a well-recognized clinical entity characterized by repeated episodes of inspiratory stridor and barking cough.1,2 The cause of this disorder, however, is not known. Some clinical similarities to asthma have been reported.3 Many such children show a specific type of airway hyperreactivity that involves both the lower and upper respiratory tracts.4 Their episodes of croup might be due to a triggering event that interacts with some predisposition.
A significant association of recurrent croup and allergy has been reported previously.3 This led us to study the serum levels of immunoglobulin fractions (IgG, IgA, IgM, and IgE) in children with recurrent croup.
Patients and Methods.—Twenty-two children, 12 boys and 10 girls, hospitalized in 1980 for an episode of recurrent croup, were studied between two and 12 months thereafter. Only children with a minimum of three episodes entered the study.
Two other groups of children in