[Evaluation of the sequelae of occupational asthma]

Current knowledge of the evolution of occupational asthma is based on few clinical studies in groups of patients sensitized to red cedar, colophony, crab boiling water and organic isocyanates. Whatever the sensitizing agent, respiratory sequelae appear to be very frequent (50% or more of subjects removed from exposure) and characterized by the persistence of an asthmatic condition with a variable degree of severity. For the greater part of these cases certain features at the time of diagnosis assessment appear to be of prognostic value for evolution: age, duration of occupational exposure, duration of symptomatic exposure, presence of spirometric alterations, degree of bronchial hyperreactivity. In all cases persistence of exposure after diagnosis produced unchanged or worsened symptomatology as a consequence. After removal from exposure the manner of evolution may be classified in three groups (1. recovery, 2. intermittent attacks lasting more than one month after exposure exclusion, 3. persistence of an airflow obstruction); particularities of their distinctive course are to consider when evaluating sequelae: symptomatology, degree of bronchial hyperreactivity, presence of airway obstruction, need for long-term steroid therapy, impossibility to find another employment on account of asthmatic attacks due to effort in coldness or to atmospheric pollutants, finally the course of intermittent attacks which does not allow a full appreciation of the severity of sequelae before six months or even one year of allergen exclusion.