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February 10, 1997

Multiple Chemical Sensitivity Syndrome and PorphyriaA Note of Caution and Concern

Author Affiliations

From the Departments of Medicine (Drs Hahn and Bonkovsky) and Biochemistry and Molecular Biology (Dr Bonkovsky) and the Center for Study of Disorders of Iron and Porphyrin Metabolism (Drs Hahn and Bonkovsky), University of Massachusetts Medical Center, Worcester.

Arch Intern Med. 1997;157(3):281-285. doi:10.1001/archinte.1997.00440240039006

Growing numbers of patients suffering from many symptoms believe that they have a condition called multiple chemical sensitivity syndrome (MCSS). It has been suggested that this syndrome can be triggered by exposure to any of a large and usually incompletely defined number of natural and synthetic chemical substances. Major medical organizations, including the National Reseach Council and the American Medical Association, have not recognized MCSS as a clinical syndrome because of a lack of valid, well-controlled studies defining it and establishing pathogenesis or origin. Lately, some have proposed that many patients with MCSS suffer from hereditary coproporphyria. However, this purported association is based chiefly on results from a single reference laboratory of a fundamentally flawed assay for erythrocyte coproporphyrinogen oxidase. Although patients with MCSS may, at times, have modest increases in urinary coproporphyrin excretion, this is a common finding found in many asymptomatic subjects or patients with diverse other conditions (eg, diabetes mellitus, heavy alcohol use, liver disease, and many kinds of anemia). Such secondary coproporphyrinuria does not indicate the existence of coproporphyria. To our knowledge, there is no scientifically valid evidence to support an association between MCSS and coproporphyria, nor is there any unifying hypothesis for rationally linking these 2 disorders.

Arch Intern Med. 1997;157:281-285