[Bronchial asthma caused by occupational sulfite exposure].

A case is reported of a patient with episodes of bronchospasm requiring hospital admission after handling sodium bisulfite on the job. The patient had a 15-year history of bronchial asthma and concomitant rhinoconjunctivitis and a 6-year history of asthma induced by moderate exercise. His family history included a father with sensitization to mites. Skin tests, measurement of specific IgI, and nasal provocation were positive for domestic dust mites and grass pollen. Skin tests for sodium metasulfite at a concentration of 10 mg/ml were negative. A simple blind oral provocation test of sodium metasulfite (1, 5, 20, and 50 mg) in acid medium was positive at the 50-mg dose, eliciting bronchial and nasal symptoms, and a decrease in CVF, FEV1, and PEF of more than 20% over baseline values. The episode of bronchospasm has not recurred in the workplace since exposure to sodium bisulfite was eliminated. Oral provocation with metasulfite in acid medium is considered a good technique for confirming the diagnosis of these cases.