History and clinical presentation of the chemically sensitive patient.

Although no one has all the answers to the mystery of chemical sensitivity, the reality of this condition, most recently called multiple chemical sensitivities, is not in doubt. Evidence is increasing of its possible physiologic mechanisms, which will be discussed later in this volume. From the evidence and from personal and professional experience, the author believes that chemical sensitivity is not a diagnosis of exclusion, and that fixed-name diseases may have environmental triggers or complicating factors (Rea, 1990b). With appropriate preparation and environmental controls, MCS can be investigated and diagnosed in a scientific and reproducible manner.