Nonspecific bronchial hyperresponsiveness and development of asthma in children with hay fever.

It has been suggested that patients with allergic rhinitis who present nonspecific bronchial hyperresponsiveness (BHR) are those most likely to develop asthma. Therefore, a study was conducted in children with rhinoconjunctivitis to ascertain whether BHR to methacholine might predict the development of asthma in these patients. Fifteen patients with hay fever and no previous symptoms of asthma were selected. All underwent clinical symptom tests and methacholine tests, during the pollen season in the 4 consecutive years following the start of the study. At the end of this period, 5 patients had developed asthma. It may thus be affirmed that, in this group, neither the presence nor the degree of previous BHR was useful for predicting which patients would later develop asthma.