The phrase "reactive airways dysfunction syndrome" (RADS) denotes the development of a persistent asthma-like condition with airway hyper-responsiveness developing in a previously healthy asymptomatic individual within 24 hours of a single exposure to concentrated respiratory irritants.
Not all experts are certain that RADS and a close counterpart, irritant-induced asthma (IIA), are real clinical entities.
Recently, a state-of-the-art review concluded with some reservation that airway-hyper-responsiveness may be acquired as a result of non-immunogenic irritant exposures. Yet no published article on RADS or IIA has provided measurements of airway responsiveness obtained before an incriminated exposure incident, and none has quantified the intensity of the exposures.
Taken in its entirety, the current scientific evidence supports the conclusion that RAD and IIA are valid clinical disorders. Respiratory irritants can lead to asthma and rhinitis through interaction with chemical irritant receptors in the airway, leading to release of substance P from sensory nerves and neurogenic inflammation.
The reactive airways dysfunction syndrome is a chronic asthma-like syndrome resulting from a single, acute exposure to a respiratory irritant, while the reactive upper-airways dysfunction syndrome is chronic rhinitis stemming from an irritant exposure.
This dysregulation of neurogenic inflammation by chemical exposures may be an important mechanism in the toxic induction of reactive airways dysfunction syndrome and reactive upper-airways dysfunction syndrome and ma play a role in understanding the sick building syndrome and the multiple chemical sensitivity syndrome.
The etiology of adult-onset asthma is incompletely understood. High-intensity exposure to irritants is one accepted risk factor and such cases are termed RADS. The contribution to asthma of less acute exposure to irritants remains to be clarified.
Acute extreme shortness of breath, tightness in the chest, and wheezing occur with this problem.
Healthy individuals with coincidental airway hyper-responsiveness may receive a diagnosis of RADS or IIA if they report both nonspecific respiratory symptoms and irritant inhalation exposures.