Persistent airways disease caused by toluene diisocyanate.

The natural history of isocyanate-induced asthma is not well documented. We evaluated a patient who developed persistent shortness of breath, wheezing, and cough after a massive exposure to toluene diisocyanate (TDI). Despite no further occupational exposures to isocyanates, he continued to have symptoms of asthma and variable airway obstruction 12 yr later. A methacholine inhalation challenge test was markedly positive, and a bronchial challenge test to TDI produced a dual asthmatic response. This report demonstrates that sensitivity to TDI can persist for many years in the absence of further occupational exposure and suggests that some patients with TDI-induced asthma do not recover from their disease after being removed from isocyanate exposure.