Description | The reactive airways dysfunction syndrome (RADS), the reactive upper airways dysfunction
syndrome (RUDS), the sick building syndrome (SBS), and the multiple chemical sensitivity
syndrome (MCS) are overlapping disorders in which there is an intolerance to environmental
chemicals. The onset of these illnesses is often associated with an initial acute chemical
exposure. To understand the pathophysiology of these conditions, a study of the nasal pathology
of individuals experiencing these syndromes was undertaken. Preliminary data indicate that the
nasal pathology of these disorders is characterized by defects in tight junctions between cells,
desquamation of the respiratory epithelium, glandular hyperplasia, lymphocytic infiltrates, and
peripheral nerve fiber proliferation. These findings suggest a model for a relationship between the
chronic inflammation seen in these conditions and an individual's sensitivity to chemicals. A
positive feedback loop is set up: the inflammatory response to low levels of chemical irritants is
enhanced due to the observed changes in the epithelium, and the epithelial changes are
propagated by the inflammatory response to the chemicals. This model, combined with the
concept of neurogenic switching, has the potential to explain many aspects of RADS, RUDS,
SBS, and MCS in a unified way. Originally published Environ Health Perspect 105(Suppl 2):473-478 (1997) | en_US |