Multiple chemical sensitivity multiorgan dysesthesia, multiple symptom complex, and multiple confusion: problems in diagnosing the patient presenting with unexplained multisystemic symptoms.

Patients are presenting in increasing numbers with multiorgan symptoms allegedly resulting from exposure to environmental chemicals. Among the symptoms expressed by patients with alleged multiple chemical sensitivities (MCS) are profound fatigue, mental confusion, myalgia, depression, anxiety, dizziness, headache, insomnia, loss of appetite, and numbness of the extremities, all in the absence of objective physical signs. Diagnostic criteria to assess the effects of environmental agents on organ systems are sorely needed because patients with MCS often have no tissue pathology or physiological abnormalities, but often do have diagnosable psychiatric illnesses. In treating patients with MCS, the physician should first perform a complete history and physical examination, including a comprehensive evaluation of chemical exposure. If the findings strongly suggest the presence of disease related to particular organ systems, further diagnostic evaluation should be undertaken. If abnormal findings are absent, psychiatric advice may be useful. The physician should keep an open mind about MCS but must also remember that a cause-effect relationship between exposure to multiple chemicals and symptoms has not been established.