Reactive airways dysfunction syndrome (RADS): guidelines for diagnosis and treatment and insight into likely prognosis.

Reactive airways dysfunction syndrome (RADS) is defined as the sudden onset of asthma following a high level exposure to a corrosive gas, vapor, or fume. This variant of occupational asthma continues to generate controversy regarding the criteria for its diagnosis. There is also some disagreement as to the likely prognosis with this disorder. Currently, the diagnosis requires the assumption of normal premorbid pulmonary physiology and absence of bronchial hyperreactivity. Criteria for the diagnosis of RADS are discussed with a proposal for both major and minor criteria to increase the confidence of an accurate diagnosis. The pathology of RADS involves a primarily lymphocytic inflammatory response with some evidence of subepithelial thickening and fibrosis. Most patients with this condition who survive the short-term exposure to a toxicant recover completely without significant clinical or physiologic sequelae. The issue of low-level RADs remains controversial and problematic as a tenable diagnosis, and will require further careful investigation to evaluate the premise that chronic, low-level toxicants are capable of leading to such a condition. More likely, most of the cases which have been reported represent preexisting asthma and/or expressions of an atopic predisposition.