[A case of hypersensitivity pneumonitis induced by toluene diisocyanate presenting with transient...

A 50-year-old male spray paint worker was admitted with non-productive cough and dyspnea on exertion. Chest X-ray and chest CT showed diffuse interstitial shadows in the bilateral lung fields. After admission, the symptoms and chest X-ray findings improved over several days, and he was followed as an outpatient. He then developed nocturnal dyspnea with wheezing and dry cough every day. About two months later, chest X-ray showed more severe diffuse interstitial shadows which did not disappear after admission. Bronchoalveolar lavage and transbronchial lung biopsy revealed allergic exudative interstitial pneumonia, and he was treated with steroid therapy. Paint contains toluene diisocyanate, and challenge test to toluene diisocyanate was positive. In the early course, this case presented with bronchoconstriction; bronchial reversibility and bronchial hyperresponsiveness to methacholine were positive. Bronchoconstriction may cause worsening of respiratory symptoms in patients with hypersensitivity pneumonitis induced by isocyanates.