[Non-allergen bronchial hyperexcitability and asthma: single and serial measurement]

Non-specific bronchial hyperresponsiveness (NSBH) is an essential characteristic of asthma. Its absence in a symptomatic individual virtually excludes asthma. Its presence is not synonymous with asthma although, in the absence of other obstructive or restrictive pulmonary conditions, it strongly suggests the diagnosis. The severity of NSBH is related to the degree of bronchial inflammation. Changes in NSBH are more frequent, although not constant, in late asthmatic reactions. The measurement of NSBH is useful in confirming or excluding a clinical diagnosis of asthma. It can also help in assessing the need for medication. Serial assessment of NSBH can be a useful tool in the follow-up of an asthmatic subject or in a subject investigated for occupational asthma although figures for sensitivity and specificity are low and preclude its routine use in these circumstances.