Irritant-Induced Asthma: Diagnosis And Management

, University of South Florida College of Medicine, Tampa, Fla.

In This Article

Abstract and Introduction


Occupational asthma is considered to be the most common occupational lung disease in industrialized countries. Two types of occupational asthma have been recognized and are differentiated only by a latency period. Occupational asthma without a latency period is often termed irritant-induced asthma (IIA). The Reactive Airways Dysfunction Syndrome (RADS) is the best known and best characterized form of IIA. The abrupt onset and persistence of asthmatic symptoms after a toxic inhalation exposure are distinctly different from the more protracted onset of immunologic occupational asthma, the second type of occupational asthma. Not all experts agree that RADS is a real and distinct clinical entity. Most studies and reviews, while acknowledging the current gap in our knowledge of the epidemiology, pathogenesis, and pathologic findings, agree that the available scientific evidence supports the conclusion that RADS and IIA are valid disorders.


Occupational asthma is not a new disease. In the fourth century BC, Hippocrates described asthma in tailors, fishermen, and metal workers. In 1713, Ramazzini noted urticaria and shortness of breath in grain workers exposed to organic dusts. Since that time, a variety of dusts, vapors, and gases have been associated with the development of asthmatic symptoms. Even with this long history, interest in workplace-induced asthma did not gain momentum until the 1960s when clinical and research questions increased dramatically.

Occupational asthma is not uncommon. In the US, it has been conservatively estimated that 2% to 5% of all asthmatics, or about 600,000 individuals, acquired their asthma in the workplace. Moreover, asthma is now the most common form of occupational lung disease in many industrialized countries.

Despite the increased prevalence of occupational asthma, increased recognition of the disorder, and an enhanced knowledge base, a fundamental problem remains: that of establishing a uniformly accepted definition of this entity.


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