Etiologic agents in occupational asthma

To date, about 250 agents have been identified as specific causes of occupational asthma with latency in the workplace. Isocyanates are widely used in many industries and are the leading cause of occupational asthma. The prevalence of isocyanate-induced asthma in exposed workers is nearly 10%. In the last decade, protein allergens in nat ural rubber latex gloves have emerged as an important cause of work-related respiratory allergic and skin disorders, especially in health-care workers. Agents that cause occupational asthma (OA) are classified as either high-molecular-weight (HMW) agents derived from natural plant and animal sources or as low-molecular-weight (LMW) chemicals. Occupational agents can be subdivided into those that are IgE-dependent and those that are IgE-independent. Asthma induced by these two groups of agents differs in clinical presentation, type of asthmatic reaction induced during inhalation challenge, and characteristics of people at risk. Chlorine and ammonia are the most common occupational agents that can induce occupational asthma without latency. The primary treatment of occupational asthma is strict avoidance of exposure to the sensitizing agent.