Recurrent nocturnal asthma after bronchoprovocation with Western Red Cedar sawdust: association with acute increase in non‐allergic bronchial responsiveness

Abstract

Recurrent nocturnal asthma following a single exposure to Western Red Cedar sawdust was documented by measurements of peak flow rates in 2 sensitized subjects. The nocturnal asthma followed a dual asthmatic response in the 1st subject and a late (non-immediate) asthmatic response in the 2nd. Both subjects developed a 10-fold reduction in the dose of histamine required to decrease the FEV1 [forced expiratory volume in 1 s] by 20%. This cedar-induced increase in non-specific bronchial reactivity was maximal at the time of the recurrent nocturnal asthma, and persisted after nocturnal asthma had ceased and after FEV1 had returned to normal. Thus, the enhanced non-specific bronchial reactivity which occurs following late asthmatic responses to bronchial challenge may be the cause of recurrent nocturnal asthma following single exposure to a sensitizing agent.