HIGH PREVALENCE OF MOLLUSK SHELL HYPERSENSITIVITY PNEUMONITIS IN NACRE FACTORY-WORKERS

Following the discovery of hypersensitivity pneumonitis caused by the inhalation of mollusc shell dust in two workers from a nacre-button fa ctory, the health status of 26 workers employed in sawing mollusc shel ls was investigated. The evaluation included the administration of two questionnaires and radiological, functional and immunological assessm ents of all workers at the outset and 1 year later, when hygienic and therapeutic measures had been taken. Six workers, in whom specific inh alation challenge test was positive, were diagnosed with mollusc shell hypersensitivity pneumonitis, thus yielding a prevalence of 23%, Evid ence of diffuse lung disease and systemic symptoms was found in these patients, Nonspecific bronchial hyperreactivity was also found more fr equently in patients with mollusc shell hypersensitivity pneumonitis, Specific immunoglobulin G (IgG) level and specific skin testing failed to differentiate patients with mollusc shell hypersensitivity pneumon itis from other exposed workers; whereas, nonspecific skin testing, wh ich was impaired in the patients, did differentiate, Bronchoalveolar l avage and transbronchial biopsy performed in patients with mollusc she ll hypersensitivity pneumonitis were consistent with the disease, Remo val from an environment containing mollusc shell dust was followed by regression of clinical, radiological and functional changes, The clini cal picture of the 20 workers who did not present mollusc shell hypers ensitivity pneumonitis remained unchanged, but functional decline was observed despite improvement in the environmental conditions of the fa ctory. This report describes the first series of patients with mollusc shell hypersensitivity pneumonitis studied, and underlines the import ance of careful follow-up of workers occupationally-exposed to mollusc shell dust.