Résumé
Terephthaloyl chloride, a chemical of low molecular weight, is used as an intermediate by a fabric manufacturing industry. It is known to cause gastrointestinal, respiratory and skin irritation. However, it has not been reported as a cause of occupational asthma till now. We report a case of occupational asthma caused by prolonged exposure to terephthaloyl chloride in the workplace. A 38 year-old man visited at the Allergy Clinic because of cough, dyspnea and wheezing for 5 years. He had worked at a factory for 15 years where he was involved in the process of manufacturing fabrics. At presentation, he had no symptoms and showed no abnormality on physical examination. When challenged with vapor of terephthaloyl chloride, he experienced sneezing and paroxysmal cough in a couple of minutes, followed by dyspnea and wheezing at 10 min. He also experienced urticarial rashes on the face and chest. The pulmonary function tests showed an atypical prolonged immediate airway response. PC20 methacholine decreased from 5 mg/ml to 0.79 mg/ml 24 hours after the challenge. Light microscopic examination of bronchial biopsies showed loss of epithelium, thickening of basement membrane, submucosal fibrosis, and increased inflammatory cell infiltration. The immediate drop in FEV1 and urticarial rash to terephthaloyl chloride suggests the possibility of an immediate hypersensitivity immune reaction. Further studies are needed to clarify the exact mechanism of terephthaloyl chloride induced asthma.