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Epidemiologic Notes and Reports Update: Eosinophilia-Myalgia Syndrome Associated with Ingestion of L-Tryptophan -- United States

On November 9, 1989, CDC contacted all state health departments to inform them of a newly recognized syndrome involving severe, debilitating myalgias and eosinophilia (greater than or equal to 1000 eosinophils per mm3). Eosinophilia-myalgia syndrome (EMS) was reported initially from New Mexico and was associated with ingestion of L-tryptophan-containing products (LTCPs) (1,2). To better characterize this syndrome and to assess the extent of the problem, CDC and state health departments implemented a national state-based surveillance system using a standardized case-report form. State health departments have telephoned numbers of EMS cases to CDC daily, then mailed completed case report forms; this results in a timely accumulation of total numbers but a lag in availability of detailed data.

As of December 6, 730 EMS cases have been reported to CDC from 48 states, the District of Columbia, and Puerto Rico. Only Alaska and South Dakota have reported no cases (Figure 1). Four deaths have been reported in patients who met the surveillance case definition and who used LT; one death has been confirmed as directly attributable to EMS, and the others are under investigation.

As of December 6, CDC has received completed report forms from 21 states with information about 64 cases fitting the case definition. Ages of these patients ranged from 14 years to 73 years (median: 44 years); 95% of patients were non-Hispanic white, 3% were black, and 2% were Hispanic. Fifty-two (81%) were female. Sixty-three (98%) had histories of LT ingestion preceding onset of symptoms; dosage ranged from 500 mg to 5000 mg per day (median: 1500 mg per day). Fifty-eight (91%) reported onset of symptoms during or after July 1989. Of the EMS patients reported thus far, 21 (33%) have required hospitalization. Reported by: State and territorial health departments. Div of Environmental Hazards and Health Effects, Center for Environmental Health and Injury Control, CDC.


  1. CDC. Eosinophilia-myalgia syndrome--New Mexico. MMWR 1989;38:765-7.

  2. CDC. Eosinophilia-myalgia syndrome and L-tryptophan-containing products--New Mexico, Minnesota, Oregon, and New York, 1989. MMWR 1989;38:785-8.

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