Multiple chemical sensitivity (MCS) is a complex, chronic disorder characterized by multisystemic symptoms occurring in response to a wide variety of chemical odors or low-level exposures. The etiology is unknown but likely multifactorial. Patient evaluation includes a comprehensive history with a review of past medical records and a physical examination with specific attention to the affected organ systems. Laboratory evaluation is dependent on past testing and patient symptoms. It should be individualized and, although standard baseline tests are helpful, exhaustive testing is not. The evaluation is primarily designed to exclude diseases requiring specific medical therapy. Treatment approaches vary considerably depending on the treating physician and patient responsiveness; many have been adapted from those used for similar chronic illnesses of unknown etiology. Therapies utilized in MCS patients include supportive care, behavioral techniques, including desensitization, psychotherapy, chemical avoidance, and clinical ecology regimens such as provocation-neutralization protocols. The advantages and disadvantages of these approaches are discussed and the use of clinical ecology regimens is discouraged. A multidisciplinary approach similar to those used in chronic pain patients may be beneficial. Regardless of the treatment chosen, the goal should be to decrease patient disability.
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