Associations between atopy, asthma history, respiratory function and non-specific bronchial hyperresponsiveness in unselected young asthmatics.

We evaluated the relationship between bronchial hyperresponsiveness and atopic status, clinical symptoms and airway calibre in a group of Italian conscripts who reported having bronchial asthma. 126 subjects were studied. Bronchial responsiveness was measured by the methacholine test, and atopic status was assessed by skin tests. A measurable PC20 was detected in 106 subjects. On the basis of the methacholine threshold concentration the sample was divided into four categories. Subjects with a low threshold response had an earlier onset of the disease and tended to take more drugs. The four categories also differed in lung function and skin reactivity towards Dermatophagoides pteronyssinus whereas no difference was found in skin reactivity towards grasses or the overall panel of tested allergen extracts. In conclusion, we found that bronchial hyperresponsiveness is related to both clinical history and lung function, whereas the relationship with atopic status seems to be allergen specific.