The relationship between fibromyalgia and the multiple chemical sensitivity syndrome.

Fibromyalgia (FM) patients often report a high frequency of non-musculoskeletal symptoms, including those suggestive of multiple chemical sensitivity (MCS) syndrome. The objective of this pilot study was to determine the prevalence of MCS in FM patients from a university-based rheumatology practice. Self-report questionnaires were administered to determine the presence of MCS, utilizing the criteria from a recent study of the immunologic profile of patients with this disorder. Patients also responded "yes" or "no" to the presence of 48 FM-related symptoms. Thirty-three of 60 patients with FM met the criteria for MCS. Eleven of these patients also fulfilled more restrictive criteria, requiring a "higher degree" of chemical sensitivity. The symptoms and substances most frequently cited were similar to those reported in other studies of MCS. FM patients with and without MCS did not differ in other symptomatology. MCS may represent an additional symptom complex within the spectrum of FM.