A guide to the diagnosis and treatment of occupational asthma

Occupational asthma is the most prevalent form of occupational lung disease in industrialized nations. As increasing numbers of new chemicals are prod uced and new manufacturing processes are introduced, the variety of environ ments in which individuals may become exposed to respiratory sensitizers an d irritants makes diagnosing and treating this illness even more challengin g. In addition to adverse pulmonary effects, the diagnosis of occupational asthma may bring with it negative social and financial implications that ma y ultimately affect the patient's quality of life. For this reason, it is i mportant for clinicians to recognize work-related respiratory symptoms earl y on in their course, maintain a high clinical suspicion for an occupationa l cause in the diagnostic work-up of asthma, and have a high degree of cert ainty in the diagnosis. While a number of classification schemes have been proposed to simplify the diagnostic approach to occupational asthma, the in citing factors typically involve sensitization (often by an IgE mechanism), direct airway inflammation, various pharmacologic responses, or irritant r eflex pathways. Clinicians must first document the presence of asthma, then establish a relationship between asthma and the workplace, The occupationa l history is the key diagnostic tool, and clinical suspicions may be evalua ted further by serial peak expiratory flow measurements, nonspecific hypers ensitivity challenges with histamine or methacholine, collaboration with in dustrial/occupational hygienists to obtain workplace exposure measurements, and specific challenge testing at tertiary referral centers providing spec ialized laboratories. Removal from the inciting exposure is the mainstay of therapy, and pharmacologic treatment of patients with occupational asthma is similar to the treatment of patients with other forms of asthma.