Occupational asthma

The seriousness of asthma in the general population has been recognized by increased prevalence, morbidity, and mortality rates in the past 20 years. The effects of occupational asthma on health and productivity in the workplace have been so deleterious that the Occupational Safety and Health Administration targeted 1995 as a crisis year for effective remediation. Several risk factors have been identified, but all asthma is multifactorial. Inhaled chemical, physical, and microbiological agents in the form of dust, fumes, gases, and vapors may cause workplace asthma, which is mediated through pharmacologic, immunologic, or irritant mechanisms. Because of the complexity of these mechanisms after exposure to the offending agents, the clinical manifestations may be classed as immediate, delayed, or dual responses. Evaluating causation and relationship to work requires a thorough history (including detailed job description), physical examination, and definitive studies to determine the presence of bronchospasm, bronchial hyperreactivity, atopy, work-relatedness, and presence of specific sensitization. Goals of treatment for occupational asthma are to maintain pulmonary function as close to normal as possible, to maintain a normal lifestyle, and to prevent exacerbation. In occupational asthma, particularly, the patient (or the inciting cause, if known) should be removed from the offending environment as soon as possible. Specific treatment depends upon the specific offending agent, and antiasthma therapy may be needed following the guidelines of the National Heart, Lung, and Blood Institute.