Course of bronchial hyperresponsiveness in patients with occupational asthma caused by exposure to persulfate salts

OBJECTIVE: Persulfate salts are among the most frequently implicated causes of occupational asthma. The aim of this study was to describe the course of bronchial hyperresponsiveness and immunologic test results in patients with occupational asthma due to persulfate salts. PATIENTS AND METHODS: Ten patients with occupational asthma due to persulfate salts were studied. Diagnosis was based on specific bronchial challenge tests performed at least 3 years before enrollment. An exhaustive medical and work history was taken during interviews with all patients, and all underwent spirometry and nonspecific bronchial challenge testing. Total immunoglobulin E levels were determined and skin prick tests to several persulfate salts were performed. RESULTS: At the time of evaluation, 7 patients had avoided workplace exposure to persulfate salts. The bronchial hyperresponsiveness of 3 of those 7 patients had improved significantly. No improvement was observed in patients who continued to be exposed. Specific skin prick tests became negative in 3 patients who were no longer exposed at the time of the follow-up evaluation. Most of the patients continued to report symptoms, although improvements were noted. One patient, however, reported worsening of symptoms in spite of avoidance of exposure. CONCLUSIONS: Although asthma symptoms and bronchial hyperresponsiveness may persist for patients with occupational asthma due to persulfate salts, their condition seems to improve if they avoid exposure. This course does not seem to differ from that reported for other cases of occupational asthma.