A Report on Multiple Chemical Sensitivity (MCS)

The Interagency Workgroup on
Multiple Chemical Sensitivity

August 24, 1998

Predecisional Draft

Medical Evaluation


Table of Contents

V. Public Health Issues in Medical Evaluation and Care of MCS Patients

Many physicians are uncertain how to approach the evaluation and care of persons who have multiple symptoms that attribute to low-level chemical exposure. Although medical approaches and therapies differ considerably because of differing beliefs about MCS by physicians, all individuals who report suffering from chemical sensitivities should receive a competent, complete medical evaluation and compassionate, understanding care. The goal of this care should be to promote health without causing additional harm. Individuals should not be subjected to ineffective, costly, or potentially dangerous treatments. Appropriate care for well-characterized medical and psychological illnesses should not be withheld or delayed. The ramifications of recommending functional changes in workplace or home settings should be carefully considered.

Medical Evaluation

The identification of MCS is based largely on the patient's description of the symptoms and the relationship of these symptoms to environmental exposures. The evaluation of an individual for MCS should, therefore, begin a complete and detailed history, including a comprehensive exposure history. The ATSDR/NIOSH Case Study in Environmental Medicine—Taking An Exposure History (ATSDR, 1992) is a useful guide for physicians unfamiliar with taking an environmental exposure history.

MCS patients often report that their symptoms began after an accidental overexposure to a chemical, typically a solvent or a pesticide, and that their symptoms recurred following exposure to lower levels of the same chemical. Symptoms then began to occur in response to low-level exposure to an increasing number of other chemicals, often unrelated to the initiating compound. Commonly reported symptoms are listed alphabetically in Table 4 and, therefore, are not in any order of frequency of occurrence.

MCS patients often associate symptoms with such substances as colognes and perfumes, aerosol air freshener, laundry detergent, gasoline exhaust, cleaners, insecticide sprays, and cigarette smoke (Ziem, 1992; Lax and Henneberger, 1995). Miller (1995) reported that an acquired, self-identified intolerance to alcohol is notably frequent among MCS patients.

Although physical findings and the results of laboratory tests in MCS patients are typically within normal limits (ACP, 1989), the physical examination, laboratory evaluation, and psychological assessment should be sufficiently comprehensive to establish or exclude underlying and coexisting medical conditions that are amenable to treatment. Physicians should be careful not to overlook other medical conditions that are amenable to treatment in an MCS patient.

No test result or panel of results can currently identify MCS. A number of tests have been suggested for evaluating MCS or have been used in studies of patients with MCS or chemical sensitivities; such tests include immunologic assays, quantitative electroencephalography, brain electrical activity mapping, evoked potentials, positron emission tomography, and single photon emission computed tomography. However, no laboratory test has been validated for sensitivity or specificity as a diagnostic predictor of MCS.

Physicians should recognize that classifying a condition as MCS does not explain the pathogenesis of the disorder. NRC's Subcommittee on Immunotoxicology advised that, "[w]henever possible, the term multiple chemical sensitivity should be replaced with a specific diagnosis to avoid the confusion between diagnosis and etiology that is inherent in the term." Some clinicians do not believe that MCS is a distinct disease and will not diagnose MCS under any circumstances (Cullen, 1994).

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Different treatment approaches for MCS have been described that parallel the proposed mechanisms. Treatment modalities that include avoidance of chemicals, megavitamins, restricted or rotation diets, provocation-neutralization, sauna detoxification, and psychiatric treatment have been suggested (Ziem, 1992; AAEM, 1992; Simon, 1992). The effectiveness of these treatments has not been demonstrated. Because the etiology of MCS is unknown, the primary goals of most physicians are aimed at relieving symptoms and improving function. With an absence of data from definitive clinical trials, no conclusions about the optimal choice of treatment modalities can currently be made. However, aggressive therapies of unproven benefit that are potentially harmful cannot be recommended.

Healthcare providers must recognize the fundamental obligation to "First, do no harm." Ill persons must not be subjected to costly, time-consuming, ineffective, or dangerous therapeutic regimens. Caregivers must ensure that their treatment methods meet the standards of peer review and tests of efficacy, and offer reports on such treatment methods in the open and critically reviewed literature.

Persons identified as having MCS also need to be educated about what is known and not known about MCS. MCS patients should be informed about the lack of proven efficacy for various treatments and cautioned about costly and potentially harmful treatments. Avoidance of some exposures may be warranted, but recommendations of complete avoidance of chemical exposures should not be made without considering the impact of such restrictions. Major lifestyle modifications can have substantial consequences, including the loss of social support and employment. Because some individuals who have symptoms of MCS suffer social and psychological consequences of their condition, healthcare should be supportive.

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