Potroom asthma: broncospasmo irritativo o da sensibilizzazione?.

Abstract The incidence of occupational bronchial asthma (potroom asthma) among workers employed on electrolytic reduction of aluminium is between 0.4 and 4%. No precise etiological agent has been identified; irritating agents are usually blamed, especially fluoridric acid, dusts, and SO2. Nevertheless, some features of potroom asthma, such as the moderate prevalence, the latency period, the progressive increase in sensitivity with continuing exposure, the appearance of symptoms several hours after the beginning of the work shift, the persistence of symptoms and of aspecific bronchial hyperreactivity even after withdrawal from the working environment, suggest the possibility of occupational asthma due to sensitization. Knowledge of the pathogenetic mechanism has direct influence on prevention: in the case of asthma due to irritants it may be sufficient to comply with the TLV, while in the case of sensitization, even low levels of exposure can be sufficient to trigger off the symptoms of bronchial asthma.